More seriously, ADHD, among others, is a working memory disorder. A way to cover this is to use "prosthetics" for it, such as a notepad that you always carry with you. If this affects you strongly, train your muscle memory to use it to note down what you were planning to do and to refer to it when you forgot.
In PC-speak, ADHDers have traded RAM for more CPU.
That's a damn good description, 4 GB of 2600 mhz ram on a 6 GHz 64 core processor and a 20gb flash disk for a hard drive.