I blogged last summer about a “geckobot”, a sticky-footed robot that could climb walls by mimicking the foot textures of geckos.
Clever folks at Carnegie Mellon are coming up with other types of wall-climbing robots, like Tankbot (with sticky tracks) or the FourBar robot (with 16 sticky feet that even lets it walk on ceilings). There’s a neat video at that link.
All of these are great improvements over older-style wall-climbing machines with suction feet, which take a lot of time and effort to stick and un-stick.
Soon your Roomba will be able to get the cobwebs out of those high corners.