I don't think the official FAQ has it but Max's axilliary FAQ site does:

http://homepages.paradise.net.nz/maxq/Hints.html for complete instructions, with pictures. but if you are a pro..

basicly, open up the character map (run: charmap) select the character, and either copy and paste, or note the character set number, and type it in Alt key + the 168 key = ¿ in my default font... other numbers, other characters.. (i made a random selection)
Note that if you use the Alt + method, you must use the keypad numbers, not the ones above the qwerty row. and if there is a zero as first character, it matters ALt+0168=¨.