payphone-project.com/usps-mailboxes/index.html - this site shows the nearest mailbox.

genesreunited.co.uk - on this site you can find out information about ancestors if you have British roots.

webamp.org - here you can run an old-school player on modern web technologies.

monalisaeffect.com - a picture following its observer.

seatguru.com is a website that helps you choose the most appropriate seat on the plane.

cardboardboxoffice.com - Here users choose a frame from a movie, and the creators of the site recreate it out of cardboard.

whattheysee.tumblr.com - the world through the eyes of museum pieces.

ctrlq.org/first - here you can find the person who posted the very first tweet, from some viral chain.

strongpasswordgenerator.com - a password generator for the most difficult passwords to crack.

haveibeenpwned.com - here you can check if an email was hacked.

lelang.ru/english/films is a site with movies with English subtitles.

stefanom.org/spc/# - this site has a solar system crash simulator.

bejofo.net/ttt - this site allows you to play tic-tac-toe with artificial intelligence.

pokemon.alexonsager.net is a site where you can cross two different pokemon.

google.com/sky - a map of the starry sky that can be viewed in the infrared or microwave spectrum.

musiclab.chromeexperiments.com/Shared-Piano/#pMyf00vwc - an online piano that multiple people can use at the same time.

shre.su/ND9J - this site can assess how much the visitor's voice fits his or her face.

demo.marpi.pl/biomes - a site where you can construct biomes.

gifprint.com - here you can turn any gif animation into a printed flipbook.

gethuman.com - here you can complain about the poor tech support of well-known companies.

beta.weknow.me is a barter knowledge exchange site, where experts from different fields and those who need their expertise meet.