Quite possibly the coolest character ever devised.
Homer is characterised by stupidity, childishness and laziness. This is typified by the many conversations he has with his brain, to which he always loses out. However, the same stupidity and childishness is generally hilarious.
Homer is also an extremely impulsive character, combined with his stupidity, this often has disastrous consequences. He is a connoisseur of crap ideas, which are acted upon hastily.
Homer is a hard man, and rarely loses a fight. Although often cowardly, if provoked Homer will and does fight. He also loves eating and having fun. Once when he was banished to Hell for being too greedy, the devil punished him by making him eat for eternity, Homer had the last laugh.
You really have to watch 'The Simpsons' to see for yourself the genius of Homer. Please also keep a look out for 'Ralph Wiggum' who's just so funny too. Make sure you watch the newer series, because I think they're funnier (Homer has 'evolved' a lot - he's become progressively dense) and the drawings are more polished.