Geotpf
My office mate likes to keep a jar of candy (mini snickers, etc) on his desk for people to dig into during the day. Various people will come by and grab some... and buy candy for the jar once inawhile too.
Anyway, we have long suspected that some of the cleaning guys were putting a huge dent in the jar throughout the week. We put a Logitech 3000 on the case

. We set the camera up about 4 feet away partially burried by some books and papers. We set the camera on the motion detection and left for the night. The candy jar was left open (lid off). We had the camera dumping files on the company webserver so we could check in from home.
Sure enough, they were into the candy pretty good. All 3 of them (Father and 2 sons). Man was it funny.. just the way they acted when they grabbed some.
The next day, we of course shared our movies with the rest of the company.. everyone loved them.. lol. We decided to see just how far they would go to get some of the chocolate goodness. The next night, we left the lid on, but not screwed on. Sure enough, they did not have a problem living the lid and taking care to make sure it was put on the same way.
The third night, we sealed it up. Screwed the lid fully on. They didn't grab any..
It was amusing for the week or so we had it up.. watching them dig deep for the ones they liked.. lol
Webcams are good for a little amature security.
Not quite $100 on the cost. Buy.com has them for $68 and $79. The clearance one has 16bit color the other has 24bit color. Did not dig deep enough to see what the other changes are.
Clearance:
http://www.buy.com/retail/clearance/product.asp?sku=70008868&loc=114
Non-Clearance:
http://www.buy.com/retail/product.asp?sku=10261818&loc=101