The Senior Fund is something you will be repeatedly be asked to give to during your senior year. In order to entice you, various 'gifts' will be offered based on level of donation (mugs, sweatshirts, etc.)
Until 2000, Columbia didn't really bother asking its seniors for money. They had bigger, wealthier fish to fry. Then, someone had the bright idea that seniors should "get into the habit of giving back." Or more sanctimoniously, the effort is "to help educate young people about the notion that as they grow older in life, they have obligations, [just as] people before them have provided for them." So, in that fateful year, Columbia became the last Ivy League school to begin actively seeking senior fund donations. By contrast, Harvard's program was established in 1965. (And you wonder why fundraising at Columbia has historically sucked?)
On the flip-side, the Senior Fund's aggressive brow beating tactics (accused of being "bankrupt" by some students) has led it in short order to be among the top of the Ivy League in its ability to extract money. (And you thought only Student Financial Services could do that?) Each year, the fund sets a successively higher goal in an attempt to surpass the previous year's mark. CC '07 met an alumni challenge by donating at an over 84% rate. SEAS '07 showed them up by achieving a 100% participation rate.
Of course no graduating class has been able to top the mother of all senior gifts - Marcellus Hartley Dodge donated $350,000 for Hartley Hall in 1903 for his graduation, which, adjusted for inflation, would be $7,861,295.27 in 2006 dollars. Suck on that CCSC.