Writing your own little personal-use web apps can be really nice - not sure how common this is, but I highly recommend it. I did it for tasks, time tracking, invoicing, and personal finances, partly because Google and others kept "upgrading" and screwing up the UI & performance of the tools I was relying on.

Each took about a day to write, and is customized exactly the way I like it; if I need a shortcut key, a weird little feature, etc. I can do it. I'm kind of an optimization / performance nut too, so they all run uber-fast, no perceptible delay from click to page / screen loaded (Sqlite is great for these kinds of things). Data is totally private and under your control. It's really nice.

However, calendar was complicated enough that I just use Google's. Might be time to rethink..