I had read through books and tutorials but wanted to go further.
I chose bingo as I play it in a care home. It is a bit tricky as there are a number of threads: one for the caller reading out the numbers and other threads for when players shout 'bingo'.
I did not use any libraries as they take a few seconds to load on my old PC. I really enjoyed writing my own animations.
Oddly, the hardest part to program was getting the shadows under the bingo boards to appear in the right place.
The best tip I found was to use closures to pass parameters to functions called with 'setTimeout'. The worst tip was to use '/* */' rather than '//' as comments - minimising utilities will remove comments anyway.
My best attempt at marketing was an announcement on freecode.com of 'World Record Set for 15000 Bingo Players'. It attracted over 120 visits. My worst piece of marketing was emailing lots of computer and womens magazines with no result.
You can increase the number of players until your browser runs out of memory. I am a little disappointed that Internet Explorer does not seem to handle this well, as Windows just says the IE has stopped responding.
The game is just one HTML page and uses no graphics files. Instead I use lots of 'div' elements to fade colours. This was because I was scared of using the GIMP.
I also collected over 3500 first names for the game. mostly from newpapers and books of biographies. They are free to use.
I do not have an Internet connection at home but use the computers in the local library. The only costs I have are the extra electricity at home and the price of a memory stick.
You can find the game at: www.sourceforge.net/p/britbingo. It is free