A beginner's guide Anyone can sign up for the MS 150, but pulling off this cycling feat takes training and equipment. By KRISTIN FINAN Copyright 2006 Houston Chronicle SURE, everyone loves the beautiful Texas countryside in spring.But from atop a bike on a two-day ride to Austin? "When you tell people you're going to ride 150-plus miles in two days, they think you're crazy," said Aaron Jacks, an MS 150 veteran and captain of the Houston-based Old School Cycling Team. "But i