It's the early to mid 1980s. A group of us are members of a school movie club -- once a week we get to stay late after school, take over the commonroom and watch a movie of our choice.
The group has some eclectic tastes, and we've all seen the blockbuster films in the cinema already anyway, so in the club we often end up watching the weirdest, wackiest, low-budget stuff that we could find in the bargain basket at the video rental shop.
This particular week, we have a sci-fi spoof movie. It is spectactularly awful: even set alongside the other junk we'd been watching, this one was so bad it actually stopped getting bad and started getting good again.
It featured a bad-guy character who was clearly a spoof of Darth Vader, but with a black tubular helmet that was probably fashioned by the props department by rolling up a piece card and taping it together.
It also featured a 'princess' fleeing from the bad guy. Somehow or other they arrive on Earth. In one particularly moving scene, she runs through someone's living room and shoves a cylinder vacuum cleaner across the floor into the path of the chasing baddies. They then spend time pulling it apart, believing it to be a droid containing vital secrets. (I can't imagine where that plot device came from...). We are later treated to a scene of a group of short aliens rummaging among the dust bunnies that they've extracted from the "droid".
As I say, it was an awful film, but annoyingly it has stuck in my memory. Or at least, a few random bits of it have. But I can't remember what it was called, or who was in it, or indeed most of the plot. And that's what's bugging me. I just can't get it out of my head, and I need to move on.
So I'm asking for help from the movie identification experts here. If you can help me to remember, it might help me to forget. :-D
[Note: Before you even suggest it, this is most definitely NOT Spaceballs]