Buffett Lunch Bubble?

The fifth annual auction of a lunch with Warren Buffett began tonight. Bids are being accepted on eBay through 10PM ET this coming Friday, June 29. But it's not a game just anyone can play. The minimum first bid is $25,000 and all bidders must pre-qualify to discourage jokesters.

Last year's winner paid just over $620,000, a stunning 77% increase over 2005's winning bid of $351,100. (For those of you who haven't been keeping track of such things, that's well above the nation's current inflation rate.)

Is there a Warren Buffett lunch bubble? Too much money chasing too few meals with billionaires? Irrational exuberance redux? We'll track the bidding and keep you updated.

Of course, the money doesn't go to Warren. It's for one of his favorite charities, the Glide Foundation of San Francisco, a group that provides social services to the city's poor and homeless.

Questions? Comments? Email me at buffettwatch@cnbc.com