Host a fundraiser. Do it at a studio, a friend's shop, a bar, a club...whatever location works best for you, and is the best bang for the buck.
The key is to spend as little money as possible on the event, so that every last penny goes towards your cause. Don't throw down a ton of money on a location, on drinks, on a band...try to get as much of this stuff as you can for free...and pay-out only to what is necessary.
You don't need to supply food and drinks...hold it at a bar or club...charge a cover at the door. Work out with the bar owner whether you get the door, a portion of the door...a portion of drinks...you name it. Usually if you bring in a fair amount of people on a slow day, you can just take the entire door fee and the bar will be happy with people buying drinks...
Jazz up your event with talented friends...bring in performers that are willing to help out for free. This could be a band...a burlesque show...a comedian...you name it.
Spice up the location with sweat equity...get some people to decorate and set things up...you shouldn't have to pay any one.
What you *don't* want to do is rent out an expensive location, pay several bands, host an open bar, and create a 'VIP' section, and then charge a ton of money for entrance....this sucks, and always fails at producing profit. Yes it might be a fun place to network and stuff...but for you and your cause...it's a money pit.
We tend to host our fundraisers at a bar (where we don't have to pay for location), we host it on an off night, and we get the proceeds of the door. We have friend's band come in...we usually have a trailer or whatnot to show...
If you want to go the shwag route...that's cool. We usually put out all of our past DVDs and shirts to the latest production. We also have a signed poster that we auction off during the night (can fetch as much as your guests are willing to haggle).
Good luck...