The city of Denver owns dozens of park tennis courts that you can play on for free, but if you have a couple bucks burning a hole in your pocket it's more than worth the price of admission to stop by the Gates Tennis Center in the Cherry Creek neighborhood. For $4 an hour per court (that's $1.25 each for a doubles match), you get your choice of twenty hard-surface courts (resurfaced this year), seven of which are well-lit for night play. Gates's center court, sunken for better viewing, is one of the best venues in the city, public or private. The tennis center also has six teaching pros on staff, and can string rackets on site.