Here's my own version of Sumof2 meets Scrabble.
http://www.evertidegames.com/2010/10/numbble-strategic-but-fun/
There aren't point values assigned to the individual tokens as per Scrabble, but you'll quickly figure out why that's not a good idea. I believe that there is already too many things to consider when you take your turn - too many numbers to add and keep track of - that it won't actually be fun.
But, I told ichbin I'd post the design. So, I'll let you guys be the judge.
Quite right. I knew it was too good to be true. Sounded too natural. Too bad that such a good App name is taken by such a poor looking game.
I have opened up the diagram to anyone with the link. It should work for you.
I considered the idea that each replacement number must be different than the ones you collect.... but I think it might unreasonably restrict the game. In fact, I think it would make it impossible to score a 5 token line if that were the case. So, I figured that I would leave it up to the player's strategy to decide. Ultimately, since you win the game by making the longest runs you can, swapping a 4 for a 4 probably represents a lost opportunity (unless it is the end of the game).
Because the number of tokens you can collect is so tight, I'm not inclined to give extra points for a 'tetris' (a five long swap). I think that simply getting that one extra token is reward enough. Ultimately, with 25 tokens on the board, the players are competing over the 55 other pieces in the bag. So, 5 out of the 55 is a big deal... it's nearly 1/5 the number you need to win.