http://radio.garden/ let's you listen to live radio broadcasts from all over the world with a neat user interface

http://pica-pic.com/ has a bunch of accurate flash recreations of old handheld games from the 80s playable in-browser

https://belowthesurface.amsterdam/en/vondsten is an archive of items found in a drained canal in Amsterdam, ranging from modern electronics to ancient tools and pottery. Many of the items are hundreds of years old, with the oldest ones dating back thousands of years, and each one has photos and detailed information about the objects.

https://mynoise.net/noiseMachines.php has a wide selection of different ambient noises that are great for background noise or as white noise for sleeping. A lot of them require a one-time donation to access, but there's tons of free ones to choose from as well.

Doesn't exactly fit with the "not big" rule, but Wikipedia's List of Unusual Articles can be a great time waster.