Hi Esme,
I remember being in the thick of this phase and having the feeling that it would never end. It does. Not soon enough, granted, but hang in there.
I agree with the earlier postings, that getting them OUT is the best solution. However, if you're penned in by snow/lack of energy, then here are the things I used to do:
Get a cardboard box and put a "letterbox" hole into it. Fold up two sheets of paper and get the twins to "post" them in turns, then take the "letters" out of the box, and re-post. Sometimes they would have to scribble an "address" on the paper first, which strung the game out a bit. Don't know if it will distract yours, but it did keep mine amused for a surprisingly long time.
Two cardboard boxes: put a cushion in, line with a blanket, and see if they want to sit in it and wrap themselves or their favourite toy in the blanket.
We used to take a mattress out of their cots and lay it on the floor with lots of cushions. They liked bouncing on the mattress. Now they bounce on our bed .
We also used to put up the travel cot (which had an opening at one end) for them to crawl in and out of (guess that's essentially the same as HMFG's suggestion of a tent).
Sometimes we hung a blanket between two chairs (two chairs with their backs to each other, blanket thrown over the backs, blanket didn't reach the floor), and got them to crawl/run through the curtain of blanket to the other side. It made them giggle.
Ours like watching the website poissonrouge dot com, it's for small children, and although you have to navigate the mouse for them, ours are entranced and blissfully quiet whilst it's up. We use it when we are at our wit's end (we've had to limit our usage ...) Both sit in their highchairs though, so I can keep them away from the keyboard (v.important for health of the keyboard).
When both of mine want to be cuddled, I sometimes found it worked to sit on the floor and put both on my stretched out legs, facing me. Then they got the bumps!
And yes to healthy snacks - mine liked cucumber sticks. They didn't actually eat it, just bit the sticks into pieces. Yellow pepper strips were also popular.
Hope that's some help, but even more, hope the phase passes soon and you get your smiley babies back.