Found this just right now!
œ∑´®†¥¨åß∂ƒ ˙∆˚¬Ω≈ç√∫˜µ aaaand last of all: © (That’s alt-g) Cick alt and another letter at the same time and magic! (Only Mac)
ermm think its the equivelent to windows alt shortcuts?
alt+1=☺
alt+2=☻
alt+3 = 
alt+4=♦
alt+5=♣
alt+7=•
alt+30=▲
etc…
well done, give yourself a pat on the back 
to get the full list windows user go to run->charmap 
And on Linux, (or at least Ubuntu) you can just press ctrl+shift and then type the unicode for your special character. I personally have an app on the task bar that allows me to quickly insert special chars.
Haha, owned
I’ve seen better. Here’s a few ones I like that I use sometimes/often/never. All these are for Mac OS X.
For taking a quick screen shot hold down ‘Shift + Command + 3’. For a selection shot use ‘Shift + Command + 4’. I use these all the time! Also note that if you add ‘Control’ to these it saves the image to the buffer rather than the desktop, so you can just paste it into any app.
And one of those useless things that’s good to know: Hold down shift while doing things like minimising windows, or opening dashboard. Slow-mo!
To close many Finder windows at the same time hold down option key and click the red button.
Press ‘Control + Option + Command + 8’ to invert colours. I think you may need to first enable this in the system preferences under Universal Access.
And if you can see the apple logos in this post, then you can use these hot tips. To write the apple logo just press ‘Shift + Option + K’
Leopard only:
In iTunes, use ‘Command + T’ to activate a silly visualizer but then in the View > Visualizer menu change it to Stix. It’s awesome, and it dances to the music.
In the Screen-saver preferences choose ‘Photos’ and then click on the little grid icon under the preview. In the options you may want to put the speed on full to make it more interesting. This is an incredibly awesome feature of Leopard that I bet hardly anyone here knows of. I love this screen saver. Only it’s slightly distracting.
If you’re feeling lazy and can’t be stuffed reading just select the text, then go 'Application_name > Services > Speech > Start Speaking Text. Make sure you’ve got the voice set to Alex as he is the only realistic one, and then he’ll read it out to you. Pretty neat. This does work in older versions of Mac OS X, however not worth it cause the other voices suck.
Also note that you can speak to your computer and get it to do stuff like empty trash, eject disks, open applications and folders, and even tell you the date, or a terrible joke. This can be enabled in the System Prefs.
Well, I hope you enjoy all those if you own a Mac!
Have fun
Cuby