timekpr will track and control the computer usage of your user accounts. You can limit their daily usage based on a timed access duration and configure periods of day when they can or cannot log in. With this application, administrators can limit account login time duration or account access hours. It has support for GNOME, KDE, and XFCE and uses time and access Linux PAM modules. It is currently limited to Ubuntu only.
todoyu is a powerful project and task management system. The core features are project handling, time tracking, time sheets, resource management, calendar, customizable reporting, keeping track of communication and decisions, invoicing directly from tracked time, and address management of customers and employees. It improves billing accuracy and timeliness, and removes risk from the billing process. A todoyu customer's clients get visibility into the project work done on their behalf. The system is extensible with additional modules. The system is completely Web based and translated in 12 languages.