Whenever I think 'quirky', two actors come to mind. One is Johnny Depp and the other is John Cusack. Both have been around for a lot of years, both are highly versatile and both can be counted on to give solid performances---especially in very offbeat films. It's interesting to see that both also have new releases in the theatres at the moment. The Raven is loosely based on Edgar Allan Poe's poem of the same name and features Cusask. Dark Shadows is a re-imagining of the 1966 TV cult classic and features Depp as an imprisoned vampire, Barnabas Collins. Truth be told, I will give both of these a pass until they come out on DVD, but we have lots of other Depp and Cusack titles that showcase their talents.
Forget the mainstream Pirates of the Caribbean franchise, we've all seen and enjoyed them, and try these from Depp: Edward Scissorhands, Rango, Don Juan DeMarco, Benny and Joon and the wonderful and truly strange Ed Wood. We also have the original tv series that launched his career and made him the heartthrob of most North American teens---21 Jump Street. I recently watched The Rum Diary and although not a great film it did qualify as mildly quirky, is well acted, and had more than enough to keep me with it.
Cusack has never really been main stream, or at least not since his days as a member of the brat pack in the 80's. Try him out in what is likely one of the most bizarre movies ever---Being John Malcovich. Also Grosse Pointe Blank and the same roll reprised in War Inc ---written by Cusack---and yes that is him doing his own stunts-he has a black belt in kick boxing.
Now to end this post, let me say that the two Johns have in their filmography to my mind several VERY scary movies. 1408 with Cusack just scares the milk and cookies out of me every time I watch it- and I can't stop watching it. And Depp is often at his best when he plays the 'in over his head' protagonist like in Sleepy Hollow. Also, From Hell (a Jack the Ripper retelling-very bloody and dark) and Secret Window.