If he is absent minded, just remind him. If you lent money to me, I might forget it (although that is unlikely because I don't like owing people money), and in that case I would be grateful of a reminder so I can pay it back, instead of annoying a friend by not paying back.
If he is not absent minded, well, just pretend that he is. Assume the best of people. Then see above: An absent minded friend will be grateful that you remind him.
Now about making up stories and lying: Don't. The fact is plain and simple: You lent him money, therefore he needs to pay it back. There is no need for explanations. There is no need to say that you need the money. There would be absolutely no need to lie about needing the money. He borrowed money, you want it back, that's enough. Especially among friends. If he doesn't have the money in his pocket, he has a bank card. If he doesn't have it with him, you can go to his home, take the bank card, go to the nearest cash machine, take the money. There's no excuse.
Hi, do you remember the 60 Euros you borrowed back then? I kinda need it [soon] [for ... or to ...]. Do you think you can pay it back soon?
Better: Hi, do you remember the 60 Euros you borrowed back then? (There should be an offer to pay back immediately, that's what you would get from me. If that offer doesn't come then...) You'll need to pay it back. Today would be a good time. (If there are any excuses then... ) You had my money for six week. Don't you think that's long enough? If you don't have the money, maybe your dad could lend it to you? Can you call him? Like, right now? Or give me his phone number, and I will call him?
If you really, really can't talk to him, for larger sums there is an alternative approach: You can sell your debt to a debt collector. You'll probably get 40-45% of the money owed. The debt collector will get 100% of the money owed from the person, who will then be your former friend.