What I'd like to do is lock the screen and have it wait a set amount of time (eg 20 mins) before it lets me log back in - so I make myself to have a break from the computer.
Is it possible to do this?
EDIT: Thanks for the suggestions - but I don't actually want something to remind me to take scheduled breaks. More something I can click when I realise I'm getting distracted and it'll immediately lock the screen for a fixed amount of time. Or even just lock screen if I can find a way to stop it letting me log in for 20 mins or so.