Yeah, a couple of times that I remember:
1. The "Lockwood month" from late 2007 pretty much paralyzed everything else.
2. The kate/arthur threads from 2006 were pretty crappy.
3. The "RIP Marc Wallice" thread got tons of attention.
4. Smartt's "Shane Diesel has AIDS" thread and all the ensuing hijinks actually got one of the ADT mods to register and post here.
5. Actually, anytime Smartt melted down was a big attention-getter.