Program: Algodoo Phun Edition; Phun 5.28
Description: Phun is the parent of Algodoo, a physics simulator being sold commercially for schools to use to teach physics. It has the best physics I have ever seen, having searched for years for a good, free physics simulator. You basically draw things, and they become real, subject to collision, gravity, appearance, friction, restitution, attraction, air friction, and others I am not able to remember as of now. There are tools for making rectangles, circles, polygons (different from rectangles and circles because these are specially scripted), springs, "tracers," and others. You can also, using another menu in it, cut, resize, fix, hinge, and perform CSG on objects among other actions. People have made everything from simple cars to typewriters to stunning images to interesting contraptions to simple computers to airplanes to skeletons with this program. Phun was and is free, whereas its child Algodoo is priced at around $41.50 (€29). I suggest Phun for obvious reasons here. Basically, Algodoo (currently - both Phun and Algodoo are promised to recieve updates) is one update ahead of Phun, so most scenes posted on Algodoo's filesharing website can be opened by Phun. Most scenes are also made by Phun, as there are more Phun users there.
This program, I think, would be useful to PortableApps because: It could go in the "Education" section, because that section is relatively small, and PortableApps could use some more diversity in its Education section. It would help Phun and Algodoo gain popularity with the people here at PortableApps.com, while simultaneously letting PortableApps gain popularity with the people at Algodoo.com.
Approximate Program Size (its size on my flash drive): 41112.71 KB; 40.1491 MB
NOTE: This program meets the "Portability" requirement. None of its files are saved to the hard drive, except for its desktop icon, which is of no importance here.
Perhaps you (whoever will convert this to a portableapp, if possible) could get in touch with the administrators and algodoo.com, or get in touch with Ken (the boss of the company that made Phun and Algodoo) or Emil (Author of Phun and Algodoo), and ask them for permission since this is not Open Source.