The new rule pack for my freeware JH NameGen program includes an Adventure Hook generator. It's available at
www.jhanson.com.
EDIT: Here's some sample output. Some can get humorously long and or convoluted, but others are short and sweet.
A long-running fight against pirates is depleting the town's food supplies.
A secretive old man mentions that a former adventurer is searching for some heroes to investigate reports of someone amassing an army of giants.
A local cleric is missing.
A well-known noble was arrested for posession of drugs, and has accused you of being a part of it.
Dock workers have asked you to nab some hobgoblins who are creating havoc in a nearby town.
Why is a blackguard stocking up on lanterns?
A family friend was seen entering a catacomb under the cemetary, and has not yet returned.
You were framed for harboring an enchanter who is a known felon.
A local celebrity's favorite bow has disappeared, and a respected craftsman is the prime suspect.
Though they are traditionally your enemies, a group of thieves want you to investigate reports of someone planning to unleash a deadly disease.