The Social Director's office was the scene of frantic activity yesterday, as Director Karin Ordahl and her girl Friday, Mary Jo Martin, prepared for the coming week-end. So varied were the offerings, the young ladies found it hard to decide which activity to push the most.

A record 650 happy, mix-it-up summer students attended the first School mixer last Tuesday, and mixer officials yesterday predicted an equally high turn-out at the second extravaganza tonight. Beginning at 8:30 p.m., the three and a half hour long get-acquainted party will cost but 50 cents, accompanied by a privilege card. Grad students can mingle for free Saturday at the Radcliffe Graduate Center.

Students who are beginning to feel the need to get out of Cambridge, if only for a day, have two possible courses of action Sunday. The Social Director's office is running a bargain tour of historic Plymouth and vicinity. Lasting 7-8 hours, the tour will cost $6 instead of the normal list price of $8.50.

Culture vultures may flock together on another bus, this one headed for Tanglewood and the special concert of the Boston Symphony and the Summer Chorus. The $8.50 ticket price includes scenic transportation and a reserved seat at Tanglewood. All those with limited cases of wanderlust should make arrangements for either trip by noon today in Matthews 4.