What $20 a week can do for you

I have and always will be one to jump on the savings money train whenever it goes by. I did the 52 week money savings challenge for a couple years which was hugely successful and left me with an extra $1300+ stored away for when Christmas rolled around, and now I'm excited to share a different moneys saving project that I've been working on that is very similar to the 52 week challenge.
$20 A WEEK.
Every week I've been putting a $20 dollar bill into a jar that doesn't get touched.  As I jump into week 19, I'm proud to say that there are $380 beautiful dollars sitting pretty for me. I have decided that L and I will be going somewhere very fun next June, and there's no way of doing that without the cold hard cash. I hate, HATE taking money out of savings, and refuse to fund our trip with money that we don't have. This seemed like one of the easier ways of putting money aside, as it is only $20 a week which is $1,040 a year. Since I started in January and will have a total of approximately 78 weeks to save, I should end up with around $1,560 total. This will definitely make a huge dent in our vacation expenses. In fact, I'm almost a quarter of the way through already! It's so easy to put cash away and forget about it!
If you don't consider yourself a cash carrying person, no problem! Every time you swipe your debit card, you usually have the option to get cash back. Take $20 from there each month and you'll barely notice. 
Why don't I just put it into savings where it can gain interest and not get lost or spent? Any money that goes into savings doesn't come out. ever. In fact, the only reason that I will be taking money out of my savings within the next five years will be to either buy a house, buy a car, or an emergency. So if I put it in there, I would become attached to the fact that it was there, and would never, ever take it out. That wouldn't be the worse thing in the world, however I am specifically setting these doll hairs aside to spend on L and I, and I want us to reap the rewards of 78 weeks of diligent savings. I used to have a coin jar with over $1000 dollars in quarters that was going to take me to Bermuda. Then, my smart, financial boyfriend talked me into investing it into my retirement... so there went that trip ;) More on that later!
What's the easiest way for you to save up for something?