If you're after seriously amateur comedians then Open Mic Monday Night at the Newmarket Hotel is for you. You're guaranteed some genuine funnies from the MC who is an old hat at this sort of gig and you definitely won't be short of crazy entertainment. Sometimes a newby will bomb so terribly that you can't help but laugh. Starts at 7 and finishes at 10ish.
If it's cheap drinks and a rowdy atmosphere you're after then the seemingly random comedy night at City Lights Backpackers is right up your alley. The crowd are up for a good time, playing pool and having a bit of a dance between acts. However if you're super keen on actually being able to hear the comedians over the rabble then this definitely isn't for you. A plus is the agro comedians throwing tantrums at totally oblivious backpackers. Monday nights at 8pm.
The most fantastic venue for comedy is, without a doubt, the Powerhouse. Livewire is held on Sunday evenings and this comedy show is the most professional and hilarious Brisbane has to offer. These comedians are carving out serious careers and their excitement is catching. The audience joins in and is only to happy to be part of the fun. The eternally classy Powerhouse has drinks and nibbles to suit everyone as well as comfortable seating (if you get in early!). Highly recommended, even if you're not much of a comedy buff. Starts at 6:30pm on Sunday.