What you guys do with old laptops?

[cdev]

I would start by - with your external monitor, installing installing some different flavors of Linux on an external HD- Distrowatch.com is a good site that has links to a great many task specific distributions-

find one that interests you that works well on the hardware. If you use an external USB disk you can keep the old install too.

Or you could put it in an enclosure and use it in some part of your house where a computer would be useful, maybe as your workbench computer?