Wish I hadn't read this!!
http://www.howtogeek.com/260726/googles-best-hidden-games-and-easter-eggs/
well, there's a couple of hours I'll never get back....
but, fun times, good memories though.
And don't forget Google's April fools spoofs, TiSP (Toilet Internet Service Provider) was my favourite.
https://archive.google.com/tisp/index.html
Lot's of others as well - https://en.wikipedia.org/wiki/List_of_Google_April_Fools%27_Day_jokes