Question: do with an old laptop?
Answer: But, first: Assess its condition. ... 
The old standby: Install Linux. ... 
Turn it into a Chromebook. ... 
Make your own network-attached storage (NAS) system. ... 
Build your own home media center. ... 
Donate its brain to science. ... 
Turn it into a webcam. ... 
Turn it into a digital photo frame.