Wargames sites offer hacking challenges on different categories like cryptographic, cracking, steganography, programming, Linux and Windows knowledge, logic, math and science. The difficulty of the challenges vary as well.
As any other gaming platform the more challenges you solve the more points you get and obviously there is a ranking where you can compete to be on top.
Wargames are used for beginners, skilled and experts for learning, practicing and improving their skills on different topics.
Here they are my top 10 of wargames sites

1. WeChall

Language: English
Categories: Programing, logic, Linux/Windows, steganography, crypto, exploits, cracking and more

2. root-me

Language: English, Spanish, French, German
Categories: Programing, Logic, Linux/Windows, Steganography, Cryptographic and more

3. pwnable.kr

Language: English
Categories: Programming, reversing, bug exploitation, cryptography and more.

4. HackerGateway

Language: English
Categories: Steganography, cryptography, Web

5. Reversing.kr

Language: English
Categories: Cracking and reversing

6. Hack the Box

Language: English
Categories: Bug exploitation, pentesting and more

7. Codingame

Language: English
Categories: Programing, Logic

8. Over the wire

Language: English
Categories: Linux, Programming

9. CryptoHack

Language: English
Categories: Cryptographic

10. Lord of the SQLI

Language: English
Categories: SQL injection

Bonus:

Not in english but good ones
Yashira
Language: Spanish
Categories: Programing, Logic, Linux/Windows, Steganography, Cryptographic and more
Enigmes-a-thematiques
Language: French
Categories: Cryptographic
Best aspect of Wargames is that you will always find a new challenge and nobody solves a challenge on the same way. So keep your mind moving and lets play! ;)