How about something simple?

[js85]

I learn best with the old fashion method of flashcards! Are there any good flashcard apps?

[AureliaeLacrimae]

Well, that depends whether you want to pay for the app or not. I believe there are some good free apps out there, you only need to find them. I've made it a little easier and I've found you two links which could be very useful:

http://appadvice.com/appguides/show/flashcard-apps-for-the-ipad

and

http://www.makeuseof.com/tag/6-flash-card-apps-for-android-compared-which-is-the-best/

The first one provides you with a list of few types of flashcards - some you have to buy, some are, however, free. The second link compares 6 of the applications and shows their pros and cons. Do some research and then decide which ones could work best for you. I wouldn't recommend buying apps until you've tested them and know for sure you'll use them - otherwise, it's wasted money.

Evernote Peek sounds interesting. I'd check it out if I were you.

[zabina12]

That reminds me of how I memorized math equations before, through flashcards.

It is really a simple but very useful  tool when trying to learn new things like languages. Nice to know that there are already apps for it but better if those are free apps.

[PotentialPolyglot]

Have you tried Memrise or Anki?

I use Memrise for most of my language learning and I find it very useful. A lot of people prefer to use Anki, but I haven't tried it. Memrise is completely free and Anki is free on desktop, but you have to pay for the app if you use iPhone.

[lucibi22]

I second the post about Memrise, I really like that site! It's worth mentioning that Duolingo also has a flashcard section--however, you can't make your own. But it tracks your progress and the words you haven't practiced in a while!