Holy Zarquon's Singing fish
I have a Don't Panic T shirt, obviously, and a Don't Panic face mask and a Don't Panic towel. I'm a long-term Hitchhikers Guide fan, these things are obligatory. But the Singing Fish T shirt is my favourite. It's more obscure, for one thing, only serious fans will get the reference (a Beetlejucian swearword used by Zaphon Beeblebrox). Also, people don't confuse it for a Dad's Army fan shirt and perform unrequested Corporal Jones impressions when I wear it.
I've been a fan of Hitchhikers Guide since I was a teenager. I can still quote large chunks of the books (and radio series) verbatim. No author has been a bigger influence on my writing. Douglas Adams was also the script editor of Dr Who when I was growing up, and wrote the seminal City of Death episode, the one with the seven Mona Lisas.
The shirt was purchased from the official Hitchhikers Guide fan club. They used to meet in a pub 200 yards from where I worked. We used to meet, drink beer, and discuss life the universe and everything (pun intended).
The shirt is past it's best, ripped and ruined, but then again so am I, so why be judgemental.