41 Bourke St
Melbourne 3000
www.comedyatspleen.com
Spleen has a very popular comedy night on Mondays which is free. This gets quite full of people so try get in early or else you'll get a seat right up the front and in the firing line of the comedians! they also do pretty well in getting big names to host these events so you can often see some bigger names trying out new material.
If you like sitting at the bar and chatting with travelers and other friendly drinking sorts of people this is good place to come but be aware it is a bit rough around the edges.