You could simply run coax from the cable box to the TV, if I'm not mistaken, and then have the kids just turn on TV and use the TV's tuner, couldn't you? And then if you're using DVI/Component on another TV input, use that in combination w/ the 1070 for when you're HT'ing.
_________________________
Model 1070
Toshiba HD-A35 & Pioneer BDP-51
Tivo Series 3
Elite 50" / Aquos 32"
Squeezebox Radio
Stereo Setup:
NAD C326BEE (50Wx2)
Elite DV-47Ai Universal SACD/DVD-A
Citypulse DA7.2x II + TXCO DAC
B&W 685s
JL Fathom F112
Denon AH-D2000 Headphones