Slang for a type of raucous laughter in which the balls jiggle uncontrollably. Can be experienced by a woman if her breasts (i.e. female balls) also jiggle uncontrollably.
That picture of the Spotted Dick you sent me was hilarballs! My testiclesstillhurt.
When an event is so ridiculously funny that the level of its humor transcends the communicative abilities of the English language. When "funny," "haha," "roflcopter" and even "lollersk8r" do not suffice. Then, it is time for the hilarbear to roar.
ZOMG, did you seeMax fall off the roller coaster and break every bone in his body? Total hilarbear.
Something that is both hilarious and terrible or horrible at the same time. When confronted with the hilarible one is torn between hysterical laughter, nausea and existential angst.