Contests at school may attract students to be interested in technology. The international Bebras contest on Informatics and Computer Literacy shows that even short tasks can provide interesting problems that give insight to technology concepts. Within 45 minutes the pupils have to solve about 18 tasks of different difficulty level. There are different task sets available for different age groups from grade 5 to grade 13. A proper design of the tasks allows school students to solve tasks that involve even advanced topics of computer science. The key idea behind these tasks is not to ask for already learned facts but to give problems that allow students to learn something about concepts that are maybe new for them. We show some typical tasks which allow to learn some aspects of informatics concepts like algorithms, structures, concurrency, information representation, proper use of ICT, modeling, etc. The performance of Bebras contests in 9 countries during the last 4 years showed an unexpected and unusual high acceptance by school students and teachers. Many thousands of students participated and got a valuable input in addition to their regular informatics lectures at school.