i've never had trouble with irony or sarcasm, or the time it takes me to understand attempts at humour of any description. one thing i have noticed is that if something's really nasty it's usually hilarious to me, and perhaps the ultimate type of humour for me is hearing about situations or speculated situations that i can imagine happening. i also find simple terms that remind me of humorous things quite amusing.
one thing i noticed when i started making friends at college and uni was that although i appreciated a witty remark or retort for being so, it wouldn't make me laugh that much. that's still the case, especially when i'm in the company of people i consider smarted or wittier than myself; it kinda leaves me thinking, I'm such a gimp, why can't i compete with him/her? which is quite funny i guess i dunno, perhaps i can conclude that subtleties just aren't my thing.
a couple of the things that make me laugh most are referring to this unsavoury, obscenely promiscuous girl i once knew as 'the syphilitic slut'; picturing this friend of a friend indulging his fetish for feather dusters; when Father Jack says banal or logical things, like 'I'm elvis', 'got out' while motioning with his hand.