Your request is pretty vague, but itIt sounds like you're just looking for any large structured dataset to play with. If you could be more specific of the type of data you're interested in, we could probably provide some more targeted recommendations.
This gist provides a good list of sample open data sets, including some curated collections by data scientists.
I particularly like Hilary Mason's research-quality dataset list.
My advice is to pick a dataset related to a subject you're interested in. Good luck!