You can choose from two main types of contributions:
With the first, each member makes a tax deductible contribution each year of up to $25,000 (inclusive of whatever amount your employer contributes for you).
Secondly, each member can also contribute $100,000 per year as a non-tax deductible contribution.
Additionally, there are a number of other special contributions you can make. For example, if you sell a small business, you can contribute up to $500,000 of the capital gain to reduce your tax.