Haha. Good suggestions up there. I rarely sit when DMing, except recently since I broke my toe. Once I'm back on my feet, I'll be ... back on my feet.Change to one of the modern systems that encourage involvement during off turns with reaction. Like MCDM.
I do have the MCDM playtest rules. Here's my concern about the "off turn reactions" concept of modern design. Remember that we recently completed the 8 month campaign of 4E. There are fewer games out there that have off turn player involvement. The issue we ran into was that all the stopping in turns dragged out the entire combat round, everyone would disengage, and that would stop people from interacting when it wasn't their turn because a round of combat would take 40 minutes or more. Of course, I haven't seen how MCDM handles it in person, but that's my hesitancy. Overall, I think just having fast turns should be enough to keep them engaged. Plus, it's a lot less headspace for me as the GM.