Pick up A-Basin's Spring 3 Pass for $130 this week through April 4 to get three days for the price of two through the rest of the season, plus additional passholder discounts on rentals ($10 off) and lessons ($50 morning lessons).
The folks at Colorado Ski Country USA have helpfully compiled a roundup of similar Spring deals from all of the member resorts remaining open after this weekend, including Steamboat's $99 Springalicious 4-Pack, Copper Mountain's $219 High Four pass, and Echo Mountain's $99 (weekday) and $119 (weekend) Family Four-Packs.
Via ColoradoSki.com:
Attention Powder Shoppers: To help everyone sort through the array of spring passes being offered now, we've detailed the different products here. Become informed because informed shoppers are finding the ski spring season's best deals. Mutli-day lift ticket discounts, stay and play packages, and early-bird reductions on 2010-11 passes are giving snow enthusiasts an extra reason to celebrate spring.