I applied online and was called about 5 days later and invited to come in for a group interview. On the phone the woman asked "Do you have any questions?" I was so excited (it's my first interview offer after 11 months of applying to jobs daily) that I said "no, thank you, I will see you then". I should've asked where to meet in the store, because I was unaware upon arrival where I should go. 2 managers sat in a corner taking notes on us. The store manager told us about himself, and then made us use construction paper and crayons to make name-tags. We were then asked to draw a picture of what we want to do at HEB (cashier, deli, etc) and then explain it. Next, they asked us to choose a product from the front (an HEB brand product) and sell it to a manager. Next, they threw down some paper, crayons, rubber bands, and paper clips and told us, as a group, we had 3 minutes build a structure that represents HEB and each of us individually have to describe it.
Next, they asked what we would not be willing to do if we got the job there (I replied "overnight stocking because of my college schedule) but many people were saying "I dont clean bathrooms" ...I dont suggest you say things like that. They told us we would get a call within 24 hours if we should come in for a 1 on 1 interview, but they ended up calling me 2 days later to schedule another interview.
Smile a lot, try and show that you have a sense of (appropriate) humor, and display knowledge about the company. Dress professionally (people were showing up in ripped jeans and t-shirts) I felt ridiculous doing arts and crafts, but just roll with it.