Gendist is a live CD generator system. It has nice features like multi-distribution CDs, support for grub, isolinux, and gfxboot boot managers, and a modules system for configuring your distribution in live mode. This system is independent from the kernel version (but need unionfs and squashfs support). It only works on Debian Sid or Ubuntu Dapper.
kexec-chooser is a thin wrapper around the kexec tool. It looks in /boot for available kernel images and associated ramdisk images, and will make the appropriate kexec call to load these into memory, and then create a stamp file. On a reboot (init level 6), if the stamp file exists, "kexec -e" will be called to execute the loaded kernel (a "warm reboot") instead of rebooting the machine.
OpenBSD Live-CD Firewall is an OpenBSD-based pf (packet filter) firewall, with NAT, squid, DNS, and a DHCP server (dnsmasq) for internal clients preconfigured. Settings and log files can be saved to a USB device. Saved settings will be restored at the next reboot. Additional security related software is available on the CD (arpwatch, honeyd, ntop, portsentry, etc.)
CADmenu makes ctrl-alt-delete more user-friendly on Linux systems. It displays a menu of actions from which you can choose to shutdown or reboot the machine, enter single user mode, or cancel and return to whatever you were doing. It's straightforward to add your own options to the menu, and it works consistently from text consoles and X.
mbldr (Master Boot LoaDeR) is a boot loader which fits into the first sector of an HDD (MBR). It allows the user to choose which partition to boot and is intended to replace an MBR that comes with DOS/Windows (fdisk /mbr). It may boot OSes above the 1024th cylinder, and Linux and BSD are also supported. mbldr is based on OS Boot Select (OS-BS) project by Thomas wolfRAM.
HeavenOS is an original, alternative 32-bit operating system for Intel 80386 compatible processors. It is made with NASM (The Netwide Assembler), and is not intended to compare to modern operating systems, but to try to get the best features and discover better ways to do things. It is intended to be a simple and pratical platform for development, running with a small amount of code.
Suspend2 allows you to hibernate your machine without needing APM, BIOS, or ACPI support. It creates an image that is saved in your active swap partitions, swap files, ordinary files or (soon) across a network. At the next system boot, the kernel detects the saved image, restores the memory from it and then it continues to run as if you'd never powered down.