Alright here goes!
If I was coming to visit for a few days I would attempt to stay pretty close to downtown so my recommendation for the hotel to stay in is The Jet. The Hotel seems like a Hotel at first but at about 10, the entire lobby turns into a bar. They have a VIP underneath the hotel as well. IF you are renting a car you can park right across the street. You are also right off of 16th street so you can have access to the train.
After checking in to the hotel you can walk over to Market street and begin your way east Bar Hopping. I would start at Pats and have a philly cheese steak and some cheap beer. Head upstairs to Crocs for some more beer and possibly a couple of shots. If you are for some reason hungry again, you can have pizza at Two Fisted Marios.
After Pizza, head east and work your way to the "Lodo" area. You can do everything from country western dance to party in the old real world Denver house. I personally find this area a little trendy, but that is where all the ladies hang out.
From here you will have a view of Coors field and if you head over to Blake Street you can head back west and go the "Sports Column" or head east and go to the Breckenridge Brewery.
I would go West to the Sports Column. The place gets pretty out of control and is actually right across the street from 1UP the arcade.
If you like to smoke Cigars pass the Sports Column and head to "The Celtic Tavern". Its an irish bar that has a cool vibe.
Save yourself some time and get back to the hotel about midnight, you have got to see the Jet in full effect. Invite all your new denver friends back for some bottle service and vip action.
Seriously the Jet is the most disfunctional ridiculous party atmosphere of all time, it does not make any sense and it is awesome.
When you wake up hungover on Saturday, take a cab to Cherry Creek. I recommmend getting to the Cherry Cricket at about 11. Have in my opinion the greatest hamburger in Denver. Cricket burger, smoked cheddar cheese and Jalapenos. Also order a side of frings (a combination of onion rings and french fries). Keep an eye on the specials, sometimes they have corndogs and other cool stuff. Also, a beer will help you get in back in shape for the game. The Cricket is where man vs. food ate a burger when coming to Denver. IF you want to be closer to the stadium go to Jack and Grill. This is where man vs food dominated the 7LB burrito. I personally think it is over-rated. Just before the game you can have a couple of beers at the original Broooklynns. I love that bar and it has some good eats as well.
You can either catch a cab to the game, or take the train. I have said it before and been called a racist, but be careful by the stadium after dark. It is not a great place in town.
When partying after the game walk back towards the Pepsi Center and you can eat at the new Brooklyn or continue back into downtown. I am assuming at this point you are somewhat inebriated. If you are not, there are some high end bars in Larimer Square to hang out. Corridor 44 has great martinis, and scotch. There is also a restaurant downstairs called Lime that is a tequila bar. Decent food, and a pretty cool atmosphere.
I am sure I will think of some other things throughout the day, but those were always my spots when I was getting after it downtown.