I know a bar that had Wii nights with bowling and other games. It was a lot of fun and it is great to play on a big screen. They ran it on wednesday nights and it did really well for a mid week event. Be careful of making beer too cheap or you get guys who come in for $2 PBRs, drink four in an hour and leave a $2 tip. You really don't need guys like that who are likely to get a DUI or who drink at your bar because they can't drive anymore.
Depending on where you are, the Island Oasis Machines are really great for frozen drink specials. You can get $7-$10 a drink and they are also good for non alcoholic drinks.
A big money maker are those Megatouch MAXX video games. You can buy them off of Ebay for $500-$1500 and then the will pull in $100-$200 a week-- cash. The really good ones will also have a internet connection so you can use them as a video juke box too, but you will need a vendor to split the cash every month. I know a guy who was pulling in $500/week just on the music.
http://cgi.ebay.com/Megatouch-Maxx-Video-Game_W0QQitemZ260514940580QQcmdZViewItemQQptZLH_DefaultDomain_2?hash=item3ca7e686a4
I think the 100 beers idea is ok but it is a lot of work to keep them in stock all the time. 20 is usually enough to bring in the folks who are looking for variety and 20 beers for a t-shirt is a bit more fair than 100. Also you don't want the bartenders to spend ten minutes to find the beers that are tucked away in a corner somewhere or run to the back up cooler during a rush.
One of my favorite bars has a big popcorn machine that is free and self serve. For 10 cents worth of popcorn, you get someone who sticks around for a second or third beer. Little salty snacks are really worth it and creates a lot of good will for your customers. I knew one bartender that brought his own big thing of goldfish crackers to give to the customers and he made a lot more than what he spent on return customers and better tips. In the bar biz we often call this kind of thing Meow mix. Check out Costco or other type stores to buy that stuff in bulk.
Also look at the lighting in your place. Is it too dark, too bright? would you take a date there? Those disco balls are very retro but people really like them if you are not running them all the time. Make sure the womens bathrooms are spotless with a good mirror and lighting for women to do touch ups. I've seen nice places that had cheap TP and women just will not go back there.
Aside from live bands, a good DJ can get a place hopping for a lot less than a live band. People drink more with DJs because they are not standing around looking at the band. They are dancing and drinking. If you have a dance floor, get a 6" shelf going around it at elbow height so people have a place to set their drinks. High small tables about 24" across are also good for people who are standing and drinking at the same time.