There's a new game fad making its mark in the Harvard Square shops this fall. It's called the Derek Bok Play-Dough kit, and it features a semester's worth of putty which can be molded into any position.

This Sunday, the real Derek Bok takes on his most natural shape. He will be at the helm when Box Jox, the rag-tag administrative conglomerate from Mass Hall, takes on Cambridge's defenders of truth and justice, the Crimson touch football team.

Bok has had his problems with the Crimson in the past, both on and off the gridiron. His off-season activity as President of Harvard has brought him some severe criticism from Harvard's daily. And on the field he has taken his share of lumps, too.

In the first encounter two years ago the Crime rallied furiously in the last quarter to tip the Jox, 23-2. Last year, in a carbon-copy rematch, the Crimson jumped to an early lead and held on to win, 23-2. Jimmy the Greek, contacted yesterday in Las Vegas, installed the Crime as a 21-point favorite, Sunday.

And besides all that, poor Bok had his ankle crushed by an inept Administration teammate two years ago in the Crimson-Jox basketball match.

Bok is planning some new tactics this year to counteract the Crime's persistent superiority in the series. Like his counterpart at Dillon Field House, coach Bok is scrapping his more flamboyant offense, one that featured a liberal sprinkling of innovation, and is adopting a more conservative style reminiscent of West Point's during the Glenn Davis days.

"We have picked up some valuable assets from the military," Bok said yesterday. "And I do not believe that our record can be fully clear until we manifest our willingness to entertain an Army program on lines compatible with our usual institutional standards."

Bok outlined an elaborate pre-game schedule for his team Sunday, beginning with an early-morning meal with Harvard vice president Upchuck Daly. Shuck has been kind enough to offer his home for the pre-game breakfast," Bok said. "And besides, I think it's a good idea to solidify with Cambridge's other breakfast Daly."

The Crimson will feature the popular front offense which revolutionized football in the sixties. "We have an unstoppable attack," Crime spokesman Freddy Boyd said yesterday. "We will never yield to pressure, from this administration or any that may follow it."

Game time is 11 a.m. behind the Stadium.