Any sysadmin who runs postgresql (or sqlite) knows he should vacuum once in a while. You didn't ? Probably because nowadays, there's an autovacuum function. But what about the Real World (you know, the big room with the blue ceiling) ?
After years of manually vacuuming the floors, I now got myself an autovacuumer to take care of my office space: the iRobot Roomba 560. This robot can drive around on the floor and cleans it. After having cleaned the room, it automatically returns to the dock where it recharges the battery.
Aside from the "cool" factor, it really does a good job. I've seen comments from people who claim that a vacuum cleaner can't run on batteries for an hour, even proving their point with calculations, but don't be fooled: the Roomba is not a vacuum cleaner like the one you already own. First, doesn't suck dirt through a 3 meter tube. Second, it isn't even a vacuum cleaner in the strictest sense: it uses brushes to pick up most of the dirt, then using a small DustBuster style vacuum engine for the finishing touch.
Overall verdict: I should have bought one sooner !