Since you're wanting to "party", don't rent a car. No driving for you!
That said you don't need one. Stay Downtown, or if on a budget, pick a hotel along the light rail. Priceline is your friend.
I have lots of recommendations for dinner, Denver has quietly become one of the best food cities in the country. What's your budget? What types of food do you like?
Falling Rock is an absolute must.
Prost is an absolute must.
Great Divide's tap-room is an absolute must.
I recommend the Cheeky Monk, particularly if you're into Belgian beers.
Before the game, hit Strange Brewing. That place is the boobies and really close to the stadium.
The view from Amato's Ale House can't be beat, plus it's a great introduction to Colorado beer. Food is decent as a bonus.
Wynkoop Brewpub has really started to produce MUCH better beer. The food has gotten alot better as well. It's in one of the best sections of Downtown (near Coors Field) as well.