Deep Rising (1998) - 30% on Rottentomatoes.
A rollicking B-movie creature feature ride that is very self aware of its tone. Treat Williams plays the hero in 'awww shucks' Indy Jones style and Famke Janssen has never been hotter. Most of the characters heros and villains alike are pretty fun and the creature itself is done well (for it's age). If you like movies like Tremors, Slither etc this is right up there.