If you are nostalgic for the old DOS games of the late 1980's and 90's, you can waste some time here https://www.dosgamesarchive.com/filetype/freeware/
I remembered ... an electronic game my cousin played all the time and he didn't want me to touch it, as I was the baby of the company.

BUT: this topic is for ... killing your time, not wasting it. When you don't want to think about anything, just sit and stare at the computer, without any mental activity, no plan, no action at all... I have such moments. Don't you;

This is another example: move the cursor on each letter, enjoy the color animation and listen ... the melody! (Volume on, again).
http://www.rrrgggbbb.com/