@articles = cache('articles') do 
Articles.latest 
end

Or:

@articles = cache(['articles', user.id], :expires_in => 15.minutes) 

Advanced Rails Recipies says: "expires_in option works only with memcached store"

Articles.latest end

Also if you'd like to have short 'cache' call in your model you can have it - add the following method to the model:

def cache(key, options = {})
ActionController::Base.cache_store.fetch(key, options) { yield }
end