I'd suggest Melaka for a day trip.

I would not call Pulau Ubin a “day trip excursion”. I used to go there just for the evening for a seafood dinner. It’s about 15 minutes on a boat from the Changi area. You can do a trip there for a few hours on an afternoon; in fact I would suggest that you offer to bring your cousin’s kids there on a Saturday or Sunday if they are old enough to ride bikes. They might enjoy it. (There is a woman who gives cooking lessons at her house on Ubin, you might look into that. I have not taken but have heard good things, see http://www.cookerymagic.com/. There is also a link to Geraldine Ismail who gives walking tours in Singapore. She is very interesting, I have been to some of her talks which she gives to the American Women’s Association but never taken a walking tour, she might be worth doing a tour with.)

Johor has some interesting bits like the Sultan’s palace and some markets, but again, I am not sure it qualifies for an excursion and am not really sure it is worth your one and only trip to go there. I agree that Malacca is very interesting and would make a good overnight trip, you can take express buses there, which would give you some countryside views. There is a good bit of colonial history preserved there, an interesting Chinatown area, and some good antique shopping. Good food as well.

The east coast of Malaysia is very beautiful, but as it is the rainy season I actually would recommend against going to any of the beaches there.

I don’t think KL is worth the time and distance. Malacca offers more for a tourist, IMO.

Sorry, can’t really recco a sports bar, but you might try the Mohamed Sultan Road area just outside the main downtown area of Singapore, this is a small area of pubs, restaurants, art galleries and shops and you probably will find a sports bar in there. Hotel bars may be showing the open as well. The Clarke Key area along the river might be another place to try.

If you're looking for a sports bar, I would recommend St James Peppermint Sports Bar, you can get the address and details here: www.gwhere.sg (search peppermint park). But then again I'm not sure if you would be able to catch the Australian Open since I mostly see football action there. Another place you might want to check out is Paulanus, a German brewery, which has great beer and a large TV. They might show tennis.

Anyway as for your excursion, it really depends. If you're an outdoorsy kinda person who loves nature, Pulau Ubin would be great. You can go cycling and there's swamps and stuff there. But if you're a shopping kind of person then going to Johor Bahru would be good because its cheap there. If you're like keen on beaches then Sentosa is quite a good choice as well.