As you might have realized, we think the user experience of checking next bus departure times could be greatly improved.
Six months ago, we thus built our own web service for MUNI buses in San Francisco, using open source technologies such as MongoDB, Django and jQuery Mobile. The 511 API was especially useful in providing very reliable departure estimates, especially when compared with other existing API providers including Google's own Maps service.
We hosted the service on Amazon EC2, tested it internally, and brought it to within reach of launch. Unfortunately, we have been so busy with other projects since then that we haven't had the time to take it to the final level. So, instead of letting it vanish into the Bermuda Triangle-esque void of uncompleted projects, we decided to open source it and share it with everyone.
Fork Where's my bus on Github!