What's going on here? מַה זֶה?

The Torah tells us that women made a special contribution to the mishkan: וְכָל־אִשָּׁה חַכְמַת־לֵב בְּיָדֶיהָ טָווּ (and all the “heart-wise women” spun with their own hands; Shemot 35:25).
What did these women contribute to the mishkan? Why does the Torah emphasize that their donations were hand-made?
Malbim says that even the richest women, who had servants who could have done the work for them, wanted to contribute gifts they had made themselves.
Ha-Ketav V’Ha-Kabbalah says that even women who had machines were so excited to donate to the mishkan, that they did their work by hand.
Rambam says this pasuk teaches us that the mitzvah to contribute money to build the בֵּית הַמִּקְדָּשׁ (Beit Ha-Mikdash, Temple in Jerusalem), and to participate in its construction—applies equally to men and women. What are they, and how do they work?