You don't get many pieces of entertainment that does justice by picking up the cliché time travel concept. Steins;Gate was made by the objective of 99% science and 1 % fiction.
The first 11 eps may make you believe that its just a light hearted sci- fi , slice of life , but after that it picks up its pace. Some of you might not understand fully what science they're babbling but you can just try to comprehend whatever you can do and if interested , get the visual novel for detailed experience.
Steins;Gate is THAT roller coaster which will make you cry , smile and shock altogether. A well crafted story+ believable theory + awesome characterization + perfect time loop = masterpiece .