What I'd really like to know is, what's the craziest use for an old phone, but to be honest I'm scared to ask.
You could always set it up somewhere in a high density area and use it as a tin-can hub. I don't have any android phones, I've been a pretty loyal iPhone user for years. But, I'm starting to see the downside of not being able to access apps that the powers that be don't deem "safe" etc. I'm thinking seriously about going Android for the first time.
Personally, I use my old phone as the "battery buffer" It plays music, games, etc, and leaves the important stuff, (redditing, maybe hubbing soon, probably both, when away from home), phone calls, etc, for my main connected phone. It's super easy to get a cheap, low power, android phone too. Heck, even decent power ones, as most phones have at least 800 mhz processors in them.
Wicked list! Thanks! I've got an old 3G Android phone (with a slide keyboard, too) that can't render an animated GIF but makes an excellent wifi-based baby computer. Unfortunately it's old enough that it may never die but it probably cannot be upgraded even if I root it. It has a tiny built-in storage, so I had to toss almost everything just to get 40 MB free but the 8 GB SD card is nearly empty. (It's running some version of Android that is too old for TuneIn.) Heck, if I could just set up some cron jobs to sync its time and not tell me about the SIM card being missing, I'd be happy to make it a guinea pig for lots of bad ideas.
I use mine as a music player mostly now. I have it plugged into my speakers and can control it using my computer but still have the ability to sit where ever I want with my laptop. The only annoying thing is that the old Google Talk app won't verify and so it freaks out once a day with a beep and I have no idea how to get it to stop.
There is no point in having a laptop if I have to be plugged in via aux on my nice speakers. I tend to move around a lot when I'm at home. I guess I could've invested in some wifi/bluetooth speakers but I didn't. :)