My phone ringtone is a lightly edited version of
They Might Be Giants singing about how the NSA are listening to the call. This seems appropriate enough, in that its main function is preventing me from ignoring a generic phone ring noise because that can't be mine because I never get phone calls.
My SMS notification is a USR modem handshaking at 28.8kbps. This causes amusing double-takes from people in their mid-30s upwards, and has a broad enough spectrum that I can sometimes hear it through wind noise when riding my bike. My email and IRC alerts are generic android alert noises, and my twitter alert once had Wowbagger wondering what bird that was.
My computer doesn't have speakers connected (I use headphones when I actually want to listen to something, or subtitles - or rant about the lack thereof - if it's just a short video). It occasionally beeps the PC speaker to get my attention to something important.
We have an alerting system that augments coded flashing lights with various comedy sounds to indicate household events: Rod Hull singing about there being somebody at the door
[1]; Elmo singing about loving trash when the bot reminds us that it's bin night; a Lemming saying "Ohno!" when the power fails, and so on. The phone ring is a Trimphone in a range of fucking cadences, and the toast alarm is a sturdy klaxon.
I really want to use a sample of Big Clive saying "One moment, please..."
[2] for something, but I've yet to work out what.
[1] This one has an even narrower age range than the dialup handshake.
[2] This usually precedes him pausing the video in order to apply Unreasonable Force to something that's been glued shut by the manufacturers