Soon I may come into the possession of two old laptops. One is a 17 inch Core 2 Duo machine and the other is a more recent 13 inch HP Stream with a Celeron and 32GB of 'flash' storage. (I suspect it's an SD card but haven't been able to open it yet to verify).
Both currently run Windows 8.1, but I have had Ubuntu working just fine on the HP Stream when messing with it in the past.
Normally I can think of things to do with older hardware if it's desktop stuff (I'm currently re-purposing an HP machine with an AMD APU for potential HTPC usage plus we have some Athlons 'laying around' for potential projects) but I have a laptop and you can't exactly play games on these or anything.
The Streams storage space is directly soldered to the motherboard. You can only expand it by adding a SD card or a small USB drive to one of the USB ports.
As for the 17 inch C2D machine, if it was running windows 7 and still has a PK that can be read. Slap Windows 10 on it and activate it with the Win 7 PK.
I didn't know that. The reason I was suspicious was the Stream seems slow for 'flash' storage. Also because Ubuntu identifies the storage as an SD card. I haven't figured out how to open it though, that'll come later. Thanks for the suggestion!
Cut a hole in your wall. Put the laptop screen in the hole. Get a compatible touch-screen overlay. Install Linux and use it as a digital picture frame, weather/clock display, music player, and even (if it's in your kitchen) look up recipe videos on youtube.
If you are interested in servers or network cracking, try that stuff with it. Install server software (ex. Filezilla) and make your own FTP and see if that's cool to you. If not, try network penetrating by installing Kali Linux and using the Aircrack suite to see how strong your network password is, or even set up a man-in-the-middle attack to learn about network penetration.
I'd install Ubuntu GNOME and SyncThing on the Stream. Use it as a portable machine to do little stuff like web browsing and managing servers. As for the Core 2 Duo box, turn it into a server with Sandstorm if you're interested in something like that. Running some LXC containers is probably also possible on it, the big limiter with laptops will be RAM though.
Kali is also not a bad idea. Kali is fun to just carry around on a dinky little netbook.
There's a lot of different things you can do with old laptops. Lot of the times I would usually turn them into Home Theater PC's, mini game servers, file servers (if you have the HDD space), wall decorations. If they are non-functional, you can practice tearing apart laptops, or learn to solder with them.