Here are some words invented on my tours, during Hebrew lessons, by friends and by me, usually in the shower. Feel free to spread them around.
This is a word I learned from Phil Rosenbloom, who came to my tour with his family, and told me about it. Medabarely is a hybrid English-Hebrew invention. Medaber is the present tense, singular, masculine of 'ledaber', to speak, hence it means 'speaking'. Barely is English, and you know it. Someone who does not speak Hebrew well can answer the question "Ata medaber ivrit" ("Do you speak Hebrew?") by Medabarely.
Magniv means 'cool' in Hebrew. Together with the English magnificent, they form a tremendously cool concoction.
Toda, תּוֹדָה, is thank you in Hebrew. In German, thank you is danke. You do notice that both have da in them, right? This is good enough occasion to weld them into one grateful word. You can say it to Germans who study Hebrew, Israelis who study German, and to any Israeli of German, Austrian and Swiss descent who offered you kind help.
Todarling, is amalgamation of Toda, תּוֹדָה, thank you in Hebrew, and darling, in English. How do you you use it? If you want to thank someone who was really really nice and speaks both languages, just utter todarling and throw in your best smile.
What is the answer for todanke, you ask? Bevakaschön, of course. It's a welding of bevakasha, בְּבַקָּשָה, which can mean please or you welcome in Hebrew, and schön, beautiful, but also used in the German you welcome, bitte schön.
Mehamazing is mehamem, מְהַמֵם, which means amazing in Hebrew, plus the English amazing. Use it to describe things which are double amazing.