Digital
Logisim
BOOLR
CircuitVerse.org
Wired Logic
Logisim Evolution
Hradla
Direct Mail
Task Coach
Todoist
Remember The Milk
Things
EssentialPIM
Todo.txt
TickTick
Google Tasks
Logisim - Logisim is an educational tool for designing and simulating digital logic circuits.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
BOOLR - Open-source digital logic simulator
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.
CircuitVerse.org - CircuitVerse is an online community driven platform to design and simulate digital logic circuits.
Things - Things is an easy to use task manager.