We all know sitting "kills", but we don't necessarily want to commit to standing throughout our entire day. The easiest answer? An adjustable standing desk like this feature-rich version from Dick Y., submitted to IKEA Hackers.
IKEA has these great adjustable legs called Vika Byske that can turn pretty much any table top into a standing desk. Dick takes it a bit further by adding multiple levels for storage and a butcher block-style countertop for sturdiness. Although it may look complicated and have a larger number of parts than your average IKEA desk, few steps are involved. Furthermore, you don't have to take it quite as far as Dick did -- he built in a power strip and added a variety of other features. You can go only as far as you need. Of course, if you'd like to just make the simple version of this standing desk you should check out this post instead.