I'm no expert but here are my thoughts.

1. Boron deficiency OR calcium deficiency OR thrips (tiny insect). Does your soil mix have micronutrients and lime in it? Do you use a balanced fertilizer? Do you notice tiny insects flying off when you touch the plant?

2. Plants too young or temperatures too hot/too cold or stress caused by #1.

3. I have no idea!

Not low boron nor low calcium. Could all be environmental.

What kind of potting mix are they in?
What size pots?
What are prevailing temperatures -- day? night?
What fertilizer -- how much & how often?
How much light? (They look very leggy.)

Jean, just go to the Photobucket album and look at pic 1. The plants are in too-small pots and are stressed. Does the OP see thrips, and that is the reason for the speculation? They'll be along soon enough to feast on the weakened plants.

Nevertheless, to salvage that situation, that is daily watering and weekly feeding. Maybe they'll tolerate that situation with that regime.

Dan

Read a thread on here a while back and several people said they couldnt grow bells and my Big Berthas in my clay soil are doing poorly. However with the 5-1-1 mix in containers I have the nicest plants I have ever had. This is my first time growing in containers and I am pleased with my tomatoes as well. One of my peppers is in a 6gal bucket and the other cont is a 8 gal trash can. Tomatoes in totes even larger. I have a Better Bush and a Bush Goliath and they are loaded with fruit...I do have a feeling they are gonna be on the small side tho. Sorta got off the subject but I do think Bell Peppers are cantankerous.

Thanks for all the follow-ups. To answer the questions:

- Zone/climate: I am in central Virginia. I planted the peppers in early April. April and May were both nice and mild (70-80s day, 60s at night). June started off hot (90+).
- Containers: standard 12" plastic contaiers. I used Strange's gardening soil, which was one of the most expensive mixes this local greenhouse is selling - they claim they use it for all of their plants too. I don't have the specific ingredients, but it looked very nice and rich. It also had those small white pellets (limestone?) that I see in the soil of professionally grown plants at Lowe's, etc. I added a generous amount of Garden Tone 3-4-4 organic fertlizer to each pot prior to transplanting. I haven't fed the plants since.
- Sun and water: the plants are in a fairly sunny place, although it's not 100% full sun (I'd say 5-6 hours a day). This is the sunniest spot I have in my small backyard... I water the plants most days, although the soil seems to retain moisture very well, so on milder days when the soil was still wet in the evening (when I usually water), I sometimes skipped watering. The plants never seemed to dry out.
- Insects. I did apply organic insecticide 3-4 times. I saw small insects here and there, as well as a moth-like creature (see photobucket album), but not necessarily signs of major infestation.

Thanks!

Try 1/4 tsp borax dissolved in water and distributed to your five plants (1/4 tsp total, not per plant). Or if you are willing to go non-organic, skip the borax and apply a balanced micronutrient fertilizer at the recommended rate. The latter option would be preferable.
The white pellets are perlite but since GroTone has 5% Ca, I think Ca deficiency is not likely.

Also, you may be overwatering. Let the soil dry out (until just before the plants begin to wilt) before you water again.

Pots are too small. Add some liquid fert weekly.

Dan

Not boron deficient.

See images here
http://www.google.com/search?q=boron+deficincey+peppers&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&hl=en&tab=wi&biw=1117&bih=653

Here is a link that might be useful: what boron deficiency looks like

Yes, there are no yellow spots at all, so boron deficiency doesn't seem to be a culprit. I've grown peppers in the same exact containers before and have never seen the crumpled leaf issue until this year. Could it be some sort of a fungus or other disease?

I'll try adding more fertilizer. What "number" (x-y-z) would work best? Someone told me fish fertilizer is good (I saw a 2-2-2) version in Lowe's - would that work?

Thanks

Jean, the first picture in your link looks very similar to the pictures posted by the OP.
Of course, there are many other potential causes of leaf crinkling in peppers (leaf curl virus for example) but leaf crinkling and crumpling is a hallmark of B deficiency.
Either way, it doesn't hurt to add a balanced micronutrient fertilizer. Look for an organic formulation that shows the entire analysis, rather than just NPK.