It hit me a while ago that entering characters which are not available on your keyboard or through your IME is much too complicated. Usually it involves opening up some character map, scrolling through hundreds of symbols to find the one you need and copy/pasting it into the application of your choice.

Not very handy. Enter Sprankle Character Map. The idea is to hit a special key combination when typing (WIN + S for Sprankle) which pops up a character map where you are typing. You then type a symbol to find similar characters and choose one from the list using either numbers or arrows + space. Here's how it looks.

This is just a prototype, but it demonstrates the idea nicely and it's actually pretty usable. Certainly better than firing up a full character map every time.

Notes:

• Sprankle is a Unicode-application and only runs on Windows 2000/XP.
• The map appears on top of the current text field. For large, multi-line text fields this is far from ideal. It would be better to have it appear at the current caret position.
• Sprankle doesn't work on Mozilla Firefox (or other applications that do special keyboard processing). If anyone has an idea on how to fix this, please tell.
• It might be better to implement Sprankle as a real IME so it integrates completely with the text field. I have no idea how to do this though, but I'm sure MSDN has some documentation about it. The downside would be that it might not work in combination with existing IMEs (e.g. for Japanese).
• Many of the symbols in the character set are not present in most fonts. Sprankle currently looks for Arial Unicode MS, the universal font that comes with XP and Office.
• It might be cool to make a JavaScript version of this, so it can be integrated on websites with CMSes like Drupal.
• You can customize Sprankle's character sets by editing sprankle.txt (UTF-16LE encoded). Right now it covers most of the Latin characters, basic Greek plus some math symbols.

Download Sprankle (source + win32 binary).