I'm not sure what part of Denver you live in, but there is an actual daycare center that is open until 10 on Friday and Saturday. My son LOVES it. He is almost 3 but has been going there since he barely turned 2. It is great to just run errands sans kids during the day or when you want to go out for a date and can't find a babysitter. It is even a bit cheaper than the standard 10 dollars an hour you will pay a babysitter.
If you are interested, their website is kidstowncenters.com
Good luck!
*correction: The center is open until 11:00 on Friday and Saturday.