The Saint Mary's Glacier
Trailhead is a short walk from the parking (parking is just north and just south of the trailhead along the road). Parking is $5 per day. The approach is a very well traveled, yet rocky approach. You can expect to see lots of people from the front range (during the spring / summer / fall). Most are just hiking, not actually skiing the glacier.
During most of the year, you can expect to be carrying your equipment until you get to the base of the glacier (which is above and to lookers right of the lake). There are some chutes you can ski (above the lake), but these can be quite dangerous (avalanche, rockfall, inability to stop) at times.
The glacier is approximately 3/4 of a mile from the trailhead. From the parking lot to the top of the glacier is just under a 1000 foot ascent. This is a great place to get in shape and practice for bigger ascents.
Note: Storms do roll in pretty quickly, so be prepared for weather (don't let the droves of unprepared city slickers hiking up in shorts and a t-shirt while a thunderstorm is rolling in fool you).