Cramped crawl spaces, virtually all starships have them, and usually most players ignore them. Unless a nasty alien gets loose inside the ship, even many Gms don't give them a second thought..
Here are 30 other issues that could require some crawl space access and provide an interesting sub plot.
30 Orcish Ornamentations of Outlandish Awesomeness and Some Ordinarily Uninteresting Objects Overcome with Ogreish Opulence!

Save/Help the Halflings! They offer rewards. Material and otherwise.
How does a given species become intelligent? Why does one turn from somewhat smart to actually sentient, and another doesn't? What is the magic formula, if there is one?
This is an editted version of an article I did many years ago covering the basic information about sake.
Tips on posting and writing in general
tips on posting Societies (part of the Codex Posting Advice)
A Codex for tips about posts in the various categories
Request AdviceDiseases. Incomplete and currently abandoned
CodexRuminations on the role of Magic and Food.
CodexIt is pitch black. You are likely to be eaten by a grue.
Do not gather and heap up and store for yourselves treasures on earth, where moth and rust and worm consume and destroy, and where thieves break through and steal. Matthew 6:19 KJV
When dealing with nobility and court settings, players can sometimes skip the roleplay aspect and jump straight to behavior such as, "I bow, greet all in the court, and ask the duke for his assistance." While in most scenarios this type of action is sufficient, taking it a step further can enhance gameplay (or maybe even manipulate a plotline).
A collection of healing Herbs.
Luchildsburg? Yeah I remember that place, they had the black ale that tasted so bad.
The proper names and descriptions of a sword’s parts.
A primer for mountaineering and a glossary of mountain climbing related terms.
The lowly Undead cannot be a true replacement for a living well-motivated workforce. But Undead do not tire, they do not have moods (well none worth marking), they do not require pay or lunchbreaks, and can work 24/7, if properly controled. So until activists start to fight for Undead rights, they are an interesting option.
In a fantastic world of magic, it can be assumed magic is in all living creatures to some degree, and a part of it is with concentration usable for magical purposes - humanoids are typically such users.
It is only logical, that for instance animals should have this magic, too.
Hell. A place of suffering and torment, a often used and cliche ridden place that every GM has to relate to.