As an undergraduate taking German classes, one of my primary difficulties was in retaining vocabulary, a task exacerbated by the language's word genders. It was only during my last term that it occurred to me to take the easy way out; namely, to write a flashcard program handling the tedious logistics that make such schemes useful, such as adjusting the occurrence frequency of individual words to correspond with learner familiarity.
The result is flasher, a German flashcard
program implemented in Python
Hopefully, others can benefit from this.
(The vocabulary was gleaned from the textbook
Vorsprung as fair dealing.)
On Windows, simply download flasher.zip, unzip it and run flasher\flasher.exe.