The awesome 1Bruce1 Weblog recaps various Sweet Valley High books, and it's a trip to read.
I hope they get to the one where the twins' brother, Steven, gets his girlfriend Billie pregnant, and they're freaked out for all of five seconds before everyone decides it's a great idea, including their parents. (She loses the baby, though, as always happens in these series.) Oh, and don't forget Jessica's secret college marriage! And endless high-school plots where Liz and Todd break up and get back together, break up and get back together.