I coulldn't remember the crime for which Tantalus was punished so severedly. I found
a site that said it was because he hilled his son Pelops. Now I've got to look for that.

Plops 1's impious father Tantalus 1, being a son of Zeus, was for some time a favourite
of the gods, and Zeus, they say, used to confide his plans to him. But since those who
enjoy privileges not seldom take undue advantage, also Tantalus 1 became boastful and
assumed that whatever he conceived would be allowed to such a nice fellow like himself.
So for example, he gave himself to gossip and started to report Zeus' plans to mortal
men.
Pelops 1 served as
a meal
In addition, he also felt that time could be ripe to play some jokes at the gods' expense.
Accordingly, he slain his own son Pelops 1, and cut him up serving him as an splendid
meal at a banquet of the gods. It was then that Demeter ate Pelops 1's arm, but when the
gods discovered the bizarre trick that Tantalus 1 had played on them, they, joining all
limbs together again, restored Pelops 1 to life.

Another story of eternal punishment is that of Sisyphus. Here is a URL about him.
http://www.mythweb.com/encyc/entries/sisyphus.html

Sisyphean
adj.
5< L Sisypheius < Gr Sisypheios < Sisyphos + 3AN6
1 of or like Sisyphus
2 endless and toilsome, useless, etc. !a Sisyphean task"

and then there's the related

"Main Entry: Tan·ta·lus...
2 not capitalized: a locked cellarette with contents visible but not obtainable without a key"

from M-W, or more succinctly

"locked case used to hold wine bottles"

from phrontistery http://phrontistery.50megs.com, which looks like an intriguing site to browse

(hoping-I'm-not-reinventing-the-wheel,-everyone-already-knows-about-it emoticon)