makecell

This package supports common layouts for tabular column heads in whole documents, based on one-column tabular environment. In addition, it can create multi-lined tabular cells.

The Package also offers:

a macro which changes the vertical space around all the cells in a tabular environment (similar to the function of the tabls package, but using the facilities of the array)
macros for multirow cells, which use the facilities of the multirow package;
macros to number rows in tables, or to skip cells;
diagonally divided cells;
horizontal lines in tabular environments with defined thickness.