ytdownload.py

from pytube import YouTube
import sys
import os

def get_video():
    yt_url = sys.argv = raw_input("Enter the video you want to download: ")
    to_download = YouTube(yt_url)

    print(to_download.filename)
    print(to_download.get_videos())

    # Here we are just trying to download the most basic video which each upload should have.
    video = to_download.get('mp4','360p')

    # Check if the target directory exists. If not, make it.
    if not os.path.exists('videos/'):
        os.makedirs('videos/')
    video.download('videos/')
    sys.exit()


if __name__ == '__main__':
    get_video()

Be sure that you do a pip install pytube before you run this.