Aaron Barrett of the Reel Big Fish had a side project for a while called The Forces of Evil that's got some fun stuff in a ska vein.
Professor Plum was a small ska band I really enjoyed when they were doing things (oh golly thirtyish years ago).
+1 for Skatalites, Mighty Mighty Bosstones, Reel Big Fish, RxBandits, Less than Jake
The Arrogant Sons of Bitches is one of my favorites, and not just because they spent time mic'ing a playskool xylophone for their sets. They're not as, um, clean as the Reel Big Fish but there's a ton of fun to be had with their songs.