I've recently encountered - and very much enjoyed - chocolate beer, coffee beer, chilli beer and smoked beer (the best being the 'Dirty Stop Out' smoked oatmeal stout by Tiny Rebel Brewery of Wales). The more variety the better i say - my current fave is the Tiny Rebel 'Cwtch' - an amber/red ale with a bitter, spicy, malty and - yes - tropical fruity thing going on. Delicious.