Getty Images Madonna performs onstage during the opening night of her 'Sticky and Sweet' tour at the O2 Arena on in London, England.

Working at an investment bank often involves mind-numbingly long hours.

So, inevitably, employees find ways to make the endless shifts at work a little more tolerable. There are eating contests. Constant wagering. And, perhaps most of all, there are quirky internal email lists.

We came across one of our favorites recently. It circulates around inside of one of the most respected firms on Wall Street. (We're leaving the firm nameless for fear of management reacting by firing everyone who has participated. Real kill joys, them bosses).

It's a celebrity sighting list. The basic concept is simple enough. When you spot a celebrity, you report it to the list. Most importantly, if you can get a picture of the celebrity, post it.

The quality of these pictures is usually quite poor. They are often taken on the move, in bad lighting, and with Blackberrys. Sometimes you just have to trust that the blur you are looking at is actually the person attested to by your co-worker.

Recent sightings have included Sarah Palin, Hulk Hogan, Steve Tyler, Lady Gaga and Pauly D from MTV's "Jersey Shore."

The list managers have had to crack down a bit. It seems that some people were posting pics from concerts of people performing on stage. That's not a sighting...it's a concert. So rules have been imposed.

Here are the official rules of the Celebrity Sighting List, according to a recent email from one of the list's founders.

1. Does not count if you paid to see the celebrity – e.g. Madonna at a Madonna concert. However, if Madonna was sitting next to you at a Lady Gaga show that counts.

2. Photos are optional, but highly preferred.

3. Description of situation in which celebrity was sighted is required.

4. Commentary and discussion are encouraged.

5. Sending a sighting should be done ASAP. Unless delay is unavoidable, do not send the next day, next week, etc.

Well, that sounds like fun. Got a quirky email chain at work? Send it to . Or text your own celebrity sightings to 917-740-8477.

Also, feel free to post your guess about which bank has the celebrity list in the comments below.

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