The Debriciner Rov in his sefer Be’er Moshe (7:1) brings from the Orchos Chaim that on Chol HaMoed you should eat meat, drink wine, and be B’Simcha like on Yom Tov. Although it is machlokes Rishonim if certain Halachos of Chol HaMoed are Min HaTorah or MidiRabanan, either way says the Be’er Moshe, Chol HaMoed has less Kedusha than Yom Tov itself. Therefore although you do not make Kiddush when drinking wine on Chol HaMoed, nevertheless you should say the words Mikadesh Yisroel V’Hazmanim when drinking.
With regard to Melacha on Chol HaMoed, he says that the Rishonim who hold that Melacha is only assur MidiRabanan, that is only if you do specific Melachos that are assur. However if you work the entire day as if it were a regular weekday, even they hold it is D’Oiraisa.
Although Melacha is assur, wasting time with excessive drinking, playing and “Kalus Rosh” he says, is far worse than working. At least when you work you are doing something productive for the world, as opposed to killing time with frivolity. To create the right balance he recommends a schedule similar to Yom Tov where you wake up, daven, go eat, learn half the day, and then daven mincha. After that you should go eat and drink and enjoy Simchas haChag with your family.
Important Note: We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. Please also understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.
This article has not been reviewed by the posek of the AskRevach section, Rav Peretz Moncharsh. Any questions regarding this topic and Halacha L’Maaseh may be asked to him at www.revach.net/ask