Well, it is Christmas after all, so we can forgive the idea of karaoke just this once. Saying that, if you're an Abba fan, you'll probably be hammering Abba Singbox pretty much all-year round.Yes, you guessed it, this is Abba karaoke, taking inspiration from the likes of Singstar from the consoles, but offering the added attraction of portability. Buy the app. load it up, clear your throat and you can singalong to some 'classics', scoring points along the way. The amateur level rates your timing, the Pro mode also checks your pitch.You can compare your scores by uploading to the Abba Facebook Group if you like (and if you have Abba-loving friends), but if you want to show your prowess across the back catalogue, you'll have to pay out the cash. The app is £1.79, but with that, you only get Dancing Queen. Other songs - The Winner Takes It All, Mamma Mia and Gimme, Gimme Gimme (A Man After Midnight) - are also available, but they cost a further £1.19 each. You just know more will be coming your way after you tire of those too. So if you don't want to spend big, you might want to think twice before downloading. Saying that, what price is just over £5 for hours of entertainment? A modest one when the TV is dull over Christmas, that's for sure.