Sunnyside Music Festival (mid-September)
The free Sunnyside Music Festival is a showcase of Colorado talent that takes place each year in Denver's Sunnyside neighborhood.
Louisville Street Faire
The downtown Louisville Street Faire in Louisville, Colorado brings great music to the Front Range every summer Friday from mid-June to mid-August. This fair's last performance of the year is usually the biggest with internationally known headliners.
In addition to the concert, the fair features excellent food and drink vendors, and children's activities such as arts and crafts.
When:
Summer Fridays from 5 to 10pm.
Music is typically 6:30 - 9.
Where:
Downtown Main Street in Louisville.
Schedule:
The 2013 Louisville Street Faire schedule is as follows:
June 14: CJ Chenier
June 21: Young Dubliners
June 28: Richie Furay
July 12: BoDeans
July 19: The Samples
July 26: Samantha Fish
August 2: Tab Benoit
August 9: Fireball
August 16: Dickey Betts and Great Southern (CANCELLED DUE TO ILLNESS)
I was really looking forward to seeing Dickey Betts again and hope he gets well soon and can come back to Colorado.
Chris Daniels and Freddi will be stepping in at the last minute for this concert.
More Info from the downtown Louisville web site: 
Colorado Dragon Boat Festival (end of July)
Held annually at the end of July, the Colorado Dragon Boat Festival is a colorful and tradition-filled celebration of Asian culture. The adult and youth boat racing competitions have grown every year and are an amazing event to watch. The performing arts stages feature the talent of Asian dance and music performances as well as martial arts exhibitions. A colorful and amazing festival and a great thing to do on a summer Denver weekend.
Don't miss the 2016 Colorado Dragon Boat Festival!
Colorado Free Fishing Weekend (First Weekend in June)
On the first weekend of June each year, Colorado waives fishing license requirements. This is a great chance to grab your gear out of storage and take the family to a nearby lake or stream for some serious trout fishing!
Old Globeville Days and the Orthodox Food Festival (annually in July)
The Old Globeville Days Orthodox Food Festival celebrates Denver's international immigrant heritage with a diverse selection of free entertainment and international food. The music features outstanding performers of diverse folk heritage including an amazing Celtic performance. The incredible food selection is sample sized and you purchase tickets to try the samples. One of the best things to do in Denver on a warm mid-July weekend.
Boulder Hometown Fair (Labor Day Weekend)
Each year the free Boulder Hometown Fair celebrates labor day weekend and the coming end of summer along Boulder Creek.
2017 National Park Free Days
The National Park Service offers free entrance to all National Parks a few times each year. This is a great way to explore our beautiful Colorado park lands.
U.S. Mint at Denver Free Tours (Monday - Thursday)
Denver Mint Tours are closed for construction through February 27, 2014.
If you ever wanted to know where that change in your pocket comes from, the free Denver Mint Tours are the place to find out! Tours are free of charge Monday through Thursday at the United States Mint in downtown Denver. Reservations must be made in advance through the United States Mint Tour Reservation System
The Denver Mint building is highly secure, so you will need to pass through a security screening before your tour begins. Many common items are not permitted on the tour, such as purses, check their web site for a detailed list of prohibited items. The tour itself is very informative and interesting, discussing not only how new coins are made but also America's coin making history.
When:
Year-round, Monday - Thursday.
Reservations are required.
Be at the tour entrance 30 minutes prior to your tour time.
Location:
320 West Colfax Avenue
It's just off the southern end of the 16th Street Mall near Civic Center Park.
Visit their web site for tour details and reservations:
Underhill Museum | Idaho Springs | Always Free
The free Underhill Museum is a small but quaint depiction of early life in downtown Idaho Springs, with several rooms set up to display a typical home setting in the early 1900's. The kitchen in particular is very elaborate, and during better weather the Victorian Garden is open to the public. In addition, there is an old vault, antique cash register, and many photos of Idaho Springs through the years.
This free museum earns revenue for the History Society of Idaho Springs with a bookstore located at the entrance. They have an excellent selection of Colorado books as well as a large used book inventory.
This is a nice free historical museum to visit while browsing the shops in downtown Idaho Springs. I'm no fan of tourist trap shops that are full of cheap imported junk, like many of the shops in more popular Colorado tourist destinations. The shops in Idaho Springs are not like that. Many feature locally made artisan works for reasonable prices.
Fall and Winter hours 2011-2012:
Saturday, Sunday, and Monday 11am to 5pm.
Location:
The Underhill Museum is at the western end of the strip in downtown Idaho Springs on Miner Street. Look for the sign that says "Books".
While you're in the area check out the Visitor Center and Heritage Museum at 2060 Miner Street.
Historic Idaho Springs site:
Boulder History Museum (free first Sunday monthly)
The Boulder History Museum offers free admission on the first Sunday of every month. This is a great deal and a chance for the rest of us to check out the museum's permanent displays, changing exhibits, and kids activities.
Zengo (Downtown Denver)
The first thing that hits you when you enter Zengo near the 16th Street mall in downtown Denver is the atmosphere. The low lighting, the expansive bar and the couches in the lounge all say one thing- "I am hip and young in Denver."
Loveland Ski Hooky Days (Second Thursday Monthly)
For the 2019 ski season, Loveland Ski Area and 95.7 The Party FM are offering $25 lift tickets on the second Thursday of each winter month.
They also offer a 2 for 1 ticket for the following week if you can't attend on Thursday. To get the $25 price, or the 2 for 1, you have to go to the "95.7 The Party" web site and sign up as a "Party VIP", then print the coupon.
When:
Thursday, February 14th, 2019
Thursday, March 14th, 2019
Where:
Loveland Ski Area is located off of I-70 just before Eisenhower Tunnel. Take the Route 6 exit (Exit 216) and you can't miss the ski area. Loveland is broken up into 2 distinct areas with a shuttle bus that runs between them. Loveland Valley (left off the exit) is considered the learning and training area and Loveland Basin (right off the exit) is the main ski area. A shuttle bus runs between both.
Irish Snug Denver Happy Hour (Capitol Hill)
Happy hour at the Irish Snug just south of Denver offers cheap, quality food and more than affordable drinks. Their happy hour menu is offered every day from 3-7 and 10-12. A diner will encounter traditional Irish fare, such as corned beef sliders and sangers. If you don’t like Irish food, don’t worry. The Irish Snug also offers burgers, tex mex and sophisticated American bar food.
Golden History Center and Astor House (free days)
The Golden History Center, along Clear Creek next to the Golden Library, and the Astor House Museum, offer free days from time to time. The next free day is during the winter Candlelight Walk, December 5th, 2014.
Details from the Golden History Museums web site: