Yes, Shea. You can see ALL past entries by clicking on the "Practice Bakes Perfect" clip set link at the top of any photo entered in the challenge, or by going to "Clips" in the main navigation line; then clicking on "All Sets"; and then clicking on the photo icon for the challenge set. This will reveal all entries ever entered, ordered from most recently entered to first ever entered. So to find ones for a particular challenge, you'd need to scroll back until you see the challenge number in the subtitle of the photo. Alternatively, you could go to the blog (under the Practice Bakes Perfect section of the blog), and find the original blog post about the challenge you are interested in. That blog post will indicate the start and end date of the challenge. With that info, you could return to the challenge clip set, and scroll back to that point in time (as all photos have a time stamp on them indicating when they were posted). But, I think the first way - just scrolling back til you find ones with the right subtitle - is probably the easiest way.
You can do what Ryoko said too, but then each entry is likely to come up as a separate entry, not all in one place. So I think scrolling through the set is likely easier/faster.