I upgraded my copy of WinSCP "(WinSCP is an open source free SFTP client and FTP client for Windows. Legacy SCP protocol is also supported. Its main function is safe copying of files between a local and a remote computer.") last night and during the installation, I was offered Xobni to install, too. It looked cool, so I installed it. I upgraded at home and was offered WeFi. I liked that so I installed it, too.
By now, I was intrigued. I checked up on OpenCandy, the company that does the offers, and found that there is a network of companies that allow additional products to be pushed out during the installation of their products. It looks to me as if all of the products are pretty cool, but here are my favorites: