Look at the letters in the image above. Can you spell a word by tracing a line through them?
If so, congratulations, you'd be good at SpellTower.
SpellTower is a stack if letters that can each disappear if you thread them into words.
SpellTower is an iOS game that, in its best mode, keeps shoving new rows of letters in from the bottom, requiring you to spell letters out of existence before any part of the stack of them reaches the top.
SpellTower is Tetris + Boggle.
Zach Gage, the man who made this game, says he created it in 13 days. He also claims, in bold red italics written at the bottom of a press release, that "Even my mum, who hasn't played a video game since Tetris, is addicted to SpellTower."
As long as Zach Gage is telling the truth, then we can concur that his mum has good taste. This game is so simple, anyone who plays it will feel like they should have thought of it. It's so good, that you'll play it for a while.
BUT! Do prepare to have a better experience on the iPad than on the iPhone or iPod Touch. On a non-iPad screen, the letter-squares in SpellTower are smaller than a finger-tip. Imagine you've pressed your finger to one of the letters on top of the screen and want to draw it to the next one in the word. But imagine that image up top is only on the bottom half of your phone's (the game's stack of letters is vertically stacked, after all). Unless you are an infant -- you're not, right? -- you will have trouble seeing the letters next to the letter you've touched. So you'll have to plan your spelling route in advance if you're playing it on an iPhone or iPod. That's fine, but it's not as ergonomically pleasing an experience is spelling words on the fly, as you trace your finger, on the iPad.
SpellTower [$2, iTunes]