He suffers from intense back problems, and thus only buys furniture at a special store known as The Lumbar Yard.
Hal buys Elaine a mattress, to which she reacts negatively due to the implication that he wants to sleep with her.
However, he bought it as a purely chivalrous action as he wanted Elaine to have the proper back support. He had the mattress specially made for her.
Near the end of the episode, he takes Kramer's advice and starts swimming in the East River to cure his back pain.
He was seen in:
* Bones
* Six Feet Under