This comic is about role-playing in the old fashioned way. The main comic shows the characters and in-game phenomena, while the commentary on the bottom is the off-game conversation of the players. It's supposed to be funny...
If you don't know/like pen&paper rpgs you could probably read just the comic though some things wouldn't possibly make much sense...
The players of the gaming group are not real persons and I can't identify myself in there, but many of the occuring events are based on my rpg group. And they are also using the same systems as we are: modified D&D 3.5 + critical tables & some spell lists from Rolemaster.