Mindgames is strictly for fun (you WILL have fun!! 
) so mistakes don't matter in the slightest. Here's the idea for some of our long-running games and I'll add to this list for any new ones.
MindGames is a fast moving forum with lots of input, and new games or ideas from anyone are always very welcome! Just start one up and we'll follow 
Because a lot of topics in here are on the go at one time, it's useful for this one forum (also Puzzles) not to rely on the 'three most recent topics' feature on the index page (to the right of the page) but to go to the Forum itself - otherwise things tend to get forgotten.
Here's some of the current games:
Ends-in: a suffix is chosen, eg. -ter. Through the alphabet, one word per post: alter, better, canter, etc.
Acrostics: a longish word is chosen, and in turn each oetter of the word is used to begin a word created from only the letters within that word and once only, eg:
BONAVENTURE
Bone
Overt
Nature
etc - aim is to make the longest word possible. Cut and paste the whole thing each time so we can admire the elegance of the developing acrostic.
Add-a-Letter - add a letter anywhere and rearrange as you like to make a new word each time - aim is to make the longest word possible! ie: be - bed - bead - beard - barred - rebraid - etc
Alphabetic Couplets: like ChattyStuff - only in rhyme! Two lines or the entire Iliad, each rhyme beginning with successive letters of the alphabet, on any subject.
Change a Letter: add one letter to the starting word, remove one, or change one to form a new word each time. Aim is not to block people but to keep it going. The same word not to be used immediately or we get stuck in a loop - i.e. not grasses-glasses-grasses.
Blockit - like Change a-letter: add, change, or take away one letter to make a new word but aim to END it as fast as possible with a word no-one can follow, though of course you shouldn't begin a game with one. No plurals allowed for Blockit!
Never a Crossword: Post a crossword style clue with letter count and beginning letter. Next player solves the clue and sets a new clue, which must begin with one of the letters from his answer.
A -Z of: through the alphabet on the given topic, ideas particularly needed on this one as I'm all out of ideas Popular ones in the past have been A-Z of Christmas, Pop Songs, PC Jargon, Slang, etc
Alphastory:
Add a word to tell a 26 word story, each word begins with successive letters of the alphabet e.g "Auntie Babs! Come down!" Eagerly.........
Punctuate imaginatively along the way, cut and paste it each time so we can see it develop, and let's see what we come up with![/i]
Adding One - add one letter each time, each word to begin with the last letter of the preceding one: eg arm-meet-thing-gropes-stopped....... etc
till we can go no further!
Up the Dictionary
an agreed length of word is chosen, eg 5 letters. The first player gives a word beginning with A. The next player puts a word which a) comes later in the dictionary than the previous one, and b) contains one 'crash' with the previous - that is, at least one common letter in the same position.
example:
ACORN
BLURT
DRUPE
FRILL
etc
Begins with.......
beAr, beBop, beCquerel, etc, using any prefix
Anagram ask/answer - post an anagram with a clue and a hidden answer, person who answers it sets one likewise
Word Association: follow on with the first word that comes into your head!
Link Word - link the last word with your word - Mouse Trap - trap door - door way - etc - see how long we can keep it going
Double Trouble - your word begins with the repeat letter of the word before - wiLLing - lOOse - oDDly - etc
Have fun and post lots - these are good to fill that five minute coffeebreak at your PC