Guesstimation - Brand new BBC1 series to air this summer.

Presented by Nick Knowles, The  National Lottery: Guesstimation is a brand new fast paced game show that involves the whole family.  It starts on Saturday 11th July at 8pm on BBC 1.

Each episode of Guesstimation sees two families compete against each other to win a fantastic prize. In order to walk away the victors, contestants will have to outsmart their opponents by weighing up the options and deploying their skill and judgement to make the best possible guess at what the answer might be.

Over three exciting rounds, the teams will face a series of unusual, fun and occasionally head spinning brain teasers. Each team's mission is simple: ‘guess' closest to the correct answer. And just to make things doubly tricky each thrilling round ends with a studio challenge performed by a special guest. The family that guesses closest to the result of that challenge wins the round and earns themselves an all important guess in the final. That's where the winning family will emerge triumphant and find themselves winning the trip of a lifetime.

The National Lottery: Guestimation showcases the Dream Number draw which raises funds for many of the venues that will be hosting events at the London 2012 Olympic and Paralympic Games.

Guesstimation - Its just a question of judgement.