To save you from going to the full-sized image on Flickr, there's a warning on the packet that "sugru® contains Methyltris(methylethylketoxime)silane; Gamma-Aminopropyl Triethoxysilane. May produce an allergic reaction".
Note also the blacked-out line on the package. Under the marker ink it says "Use within a year of purchase". Actually, Sugru's official shelf life is only six months. Which is a slight bummer, but I only bought one "Smart Hacks Super Pack", for £11 plus £1.26 postage to me here in Australia. So I'll probably be able to use it all before it dries up. You clearly shouldn't use the "buy a huge lifetime-supply sack for a volume discount" technique for Sugru, though.
The only thing I don't like about Sugru is the manufacturers' endless use of the word "hack". All sorts of unremarkable things are today being promoted to the status of hacks. Some of the things you can do with stuff that goes on like putty but turns into silicone rubber in 24 hours definitely qualify as hacks, but I don't think just putting a more comfortable grip on a knife, cable or nail clipper really counts.
(Several pictures in the Sugru gallery only use the stuff to put little rubber feet on some slippery object. This strikes me as a waste of this quite expensive product, since peel-and-stick self-adhesive rubber feet in all shapes and sizes are easy to find and very cheap. Sugru will probably stick better than your basic rubber foot, but since you can get more than fifty small rubber feet for about five US bucks, I think you'll have some spares.)
Here are all of the Sugru pictures on Flickr, including some neat ideas. Here's the photostream of "projectsugru / Jane ni Dhulchaointigh", which appears to be some sort of aberrant composite entity formed from the woman who invented Sugru, and the product itself. There's also a Flickr group called "Sugru Hacks" which only has six images in it so far. Perhaps I should start a "Sugru I-Refuse-To-Use-The-H-Word" group.
Apparently (PDF), methyltris(methylethylketoxime)silane is commonly used as a cross-linker in RTV silicone compositions. There are several related compounds used for the same purpose. Its MSDS (PDF) isn't very alarming.
Gamma-aminopropyl triethoxysilane, a.k.a. 3-aminopropyl triethoxysilane, seems (PDF) to be another common sealant/adhesive ingredient; it, again like several other silanes, can work as a cross-linker as well, and also as a "coupling agent" that helps polymers stick to surfaces. It seems to be (PDF) rather nastier than methyltris-blah-blah-blah. I presume Sugru contains little enough of it that most people won't suffer skin irritation. I may need to revise my plan to eat all of my Sugru, though.
(I found the above-linked PDFs on this chemical-company site.)
Before I looked this stuff up, I thought these two long-named chemicals might have been unique to Sugru. There has to be something unusual in Sugru, because it does seem to be a genuinely new product, not just some well-known industrial product being re-packaged at a huge markup for consumers, like Silly Putty or "mouse tape".
Whatever the secret herbs and spices are, though, they're not methyltris(methylethylketoxime)silane or gamma-aminopropyl triethoxysilane.