xkcd is a webcomic that has been around for a number of years and Randall is posting his 700th entry this week.
It's the only comic I read now. The ones in the paper (on the rare occasion [less than once per month] when I read a newspaper) are embarrassingly unfunny, as are most web-only comics. But xkcd has moments of insight - and is perhaps the only heir to the long-lost and Calvin & Hobbes in terms of its mix of intellect, humor, and sentimentality.
The best strips are typically one-idea jokes that have something to do with math:

But some great ones are almost more like HowToons than comics:

It's not for everyone, and some of the nerdier strips require information that I don't, and won't ever, have - but it's worth checking out.