I am a user of Telehack, an online simulation of ARPANET of the 80's, a blend of retrocomputing museum and computer game.
The programs here are written in Telehack's TH BASIC, a reimagination of the original Dartmouth University "TeleBasic" (~1965).

10 PRINT "HELLO WORLD"
20 GOTO 10

Here

• BINTREE.BAS, binary search tree visualizer
• BMH.BAS, implementation of Boyer-Moore-Horspool string search
• CHIP8ASM.BAS, CHIP-8 disassembler (that could use a little bit more love)
• CYBERPUNK.BAS, Cyberpunk 2077 hacking sim clone
• EXPONENTIAL.BAS, benchmark of linear & exponential search algorithms for counting lines in a file
• fightuser.sh one-line TRON->dot->SVG visualizer of TeleBASIC TRON tracing
• GRADIENT.BAS sRGB<->XYZ<->LAB<->CIE Lch color conversions and gradient generation tool
• HASH.BAS, djb2 hash adjusted for ieee754 float64
• HEAP.BAS, implementation of Heap's Algorithm
• INVADERS.BAS, simplistic Space Invaders demo
• LIGHTSOUT.BAS, LightsOut game clone
• LZ4.BAS, mostly working LZ4 decompression
• REPL.BAS, WiP P-code interpreter and a TH BASIC compiler for the interpreter.
• SUN.BAS, paints a sun on the terminal. Unashamedly stolen from a certain H/P/A BBS you might find you way to.
• TRIE.BAS, a hash table-backed prefix tree to support tab completion. Uses FOR..NEXT instead of GOTO/GOSUB to make integration easier. Also sports a relatively usable readline clone as a demo.
• UNDIALED.BAS, given a set of files with phone numbers, dial the numbers not in your dial /log