The Order of the Stick

If you've ever stayed up way past your bedtime playing a marathon game of Dungeons and Dragons, then this webcomic by Rich Burlew is for you. In addition to the silly (and very funny) jokes, it has a strong plot and very believable, individual, engaging characters.

My personal favorite is Roy, the Lawful Good fighter that leads the group. He is occasionally at odds with some of his more outlandish and irresponsible party members, but he manages to triumph over difficulties and some flaws in his own character time and again to keep the group together and working towards achieving their goal.

Go check it out! I strongly advise starting with #1; there is an overall plot that will lose you if you try to pick it up in the middle. That, and it really doesn't take that long to read, even though there are almost 250 strips at this point.