Thanks to reader Jennifer for noticing that TV Guide has posted the first little tidbits regarding the challenges for episodes 1-3:
Episode 1: The runaway runway hit opens its fifth season with 16 fresh designers on pins and needles: They try to make it work by creating clothes from unusual sources.
Episode 2: The designers participate in a green-themed challenge.
Episode 3: The clothiers create designs for a client's special day.
Hmmm. Unusual sources, a green-themed challenge and a client's special day. Haven't we seen these before? Let the speculation begin!