Help - rain!

We are going to Icmeler on Friday - our kids are 14 and 10 and I was wondering if anyone has any suggestions of stuff to do over there if its raining as the forecast doesn't look too good.
We have been before at this time of year and it's been nice weather so keeping the kids entertained hasn't been a problem, now if the weather isn't going to be too good I'l like to have a back up plan in place to keep them entertained.
Any ideas would be very much appreciated
Thank you

We have been before at this time of year and it's been nice weather so keeping the kids entertained hasn't been a problem, now if the weather isn't going to be too good I'l like to have a back up plan in place to keep them entertained.
Any ideas would be very much appreciated

Thank you